diff --git a/.github/update_api.py b/.github/update_api.py
index b6128b35a..ae0ea5d8f 100644
--- a/.github/update_api.py
+++ b/.github/update_api.py
@@ -1,6 +1,5 @@
-import argparse
-import tomllib
 import os
+import tomllib
 
 
 def main():
diff --git a/Makefile b/Makefile
index b7f515cd5..dc1e167b3 100644
--- a/Makefile
+++ b/Makefile
@@ -11,6 +11,7 @@ install:
 	pip install huggingface_hub
 
 format:
+	ruff check . --fix
 	ruff format .
 
 test:
diff --git a/changelog.d/add-ruff-linting.added.md b/changelog.d/add-ruff-linting.added.md
new file mode 100644
index 000000000..597070fb5
--- /dev/null
+++ b/changelog.d/add-ruff-linting.added.md
@@ -0,0 +1 @@
+Added ruff linting (ruff check) to Makefile format target with E, F, and I rule sets.
diff --git a/docs/book/programs/contrib/ubi-center/carbon-tax.ipynb b/docs/book/programs/contrib/ubi-center/carbon-tax.ipynb
index d627d7a95..b51d618c8 100644
--- a/docs/book/programs/contrib/ubi-center/carbon-tax.ipynb
+++ b/docs/book/programs/contrib/ubi-center/carbon-tax.ipynb
@@ -980,8 +980,8 @@
     }
    ],
    "source": [
-    "import plotly.express as px\n",
     "import pandas as pd\n",
+    "import plotly.express as px\n",
     "\n",
     "df = pd.DataFrame(\n",
     "    {\n",
diff --git a/docs/book/programs/gov/dcms/bbc/tv-licence.ipynb b/docs/book/programs/gov/dcms/bbc/tv-licence.ipynb
index 9e7123015..20d5c6def 100644
--- a/docs/book/programs/gov/dcms/bbc/tv-licence.ipynb
+++ b/docs/book/programs/gov/dcms/bbc/tv-licence.ipynb
@@ -121,6 +121,7 @@
    ],
    "source": [
     "import pandas as pd\n",
+    "\n",
     "from policyengine_uk import CountryTaxBenefitSystem\n",
     "\n",
     "system = CountryTaxBenefitSystem()\n",
diff --git a/docs/book/programs/gov/hmrc/child-benefit.ipynb b/docs/book/programs/gov/hmrc/child-benefit.ipynb
index 02b915df5..4bb786ce2 100644
--- a/docs/book/programs/gov/hmrc/child-benefit.ipynb
+++ b/docs/book/programs/gov/hmrc/child-benefit.ipynb
@@ -152,9 +152,10 @@
     }
    ],
    "source": [
-    "from policyengine_uk import CountryTaxBenefitSystem\n",
     "import pandas as pd\n",
     "\n",
+    "from policyengine_uk import CountryTaxBenefitSystem\n",
+    "\n",
     "parameters = CountryTaxBenefitSystem().parameters\n",
     "data = {\n",
     "    \"Date\": [],\n",
diff --git a/docs/book/programs/gov/hmrc/fuel-duty.ipynb b/docs/book/programs/gov/hmrc/fuel-duty.ipynb
index 51d676866..48a392dd7 100644
--- a/docs/book/programs/gov/hmrc/fuel-duty.ipynb
+++ b/docs/book/programs/gov/hmrc/fuel-duty.ipynb
@@ -116,9 +116,10 @@
     }
    ],
    "source": [
-    "from policyengine_uk import CountryTaxBenefitSystem\n",
-    "import plotly.express as px\n",
     "import pandas as pd\n",
+    "import plotly.express as px\n",
+    "\n",
+    "from policyengine_uk import CountryTaxBenefitSystem\n",
     "\n",
     "system = CountryTaxBenefitSystem()\n",
     "hmrc = system.parameters.gov.hmrc\n",
@@ -1053,8 +1054,6 @@
     }
    ],
    "source": [
-    "import plotly.express as px\n",
-    "\n",
     "px.line(\n",
     "    df,\n",
     "    x=\"Date of change\",\n",
diff --git a/docs/book/programs/gov/hmrc/income-tax.ipynb b/docs/book/programs/gov/hmrc/income-tax.ipynb
index 77f1fc99a..b5d30e95b 100644
--- a/docs/book/programs/gov/hmrc/income-tax.ipynb
+++ b/docs/book/programs/gov/hmrc/income-tax.ipynb
@@ -204,6 +204,7 @@
    ],
    "source": [
     "import pandas as pd\n",
+    "\n",
     "from policyengine_uk import Simulation\n",
     "\n",
     "\n",
@@ -515,9 +516,10 @@
     }
    ],
    "source": [
-    "from policyengine_uk.system import system\n",
     "import pandas as pd\n",
     "\n",
+    "from policyengine_uk.system import system\n",
+    "\n",
     "default = system.parameters.gov.hmrc.income_tax.allowances.annual_allowance.default\n",
     "minimum = system.parameters.gov.hmrc.income_tax.allowances.annual_allowance.minimum\n",
     "reduction_rate = (\n",
@@ -5635,8 +5637,6 @@
     }
    ],
    "source": [
-    "from policyengine_uk import Simulation\n",
-    "\n",
     "simulation = Simulation(\n",
     "    situation=dict(\n",
     "        people=dict(\n",
@@ -5658,8 +5658,8 @@
     "    ),\n",
     ")\n",
     "\n",
-    "import plotly.express as px\n",
     "import pandas as pd\n",
+    "import plotly.express as px\n",
     "from policyengine_core.charts import format_fig\n",
     "\n",
     "df = pd.DataFrame(\n",
diff --git a/docs/book/programs/gov/hmrc/national-insurance.ipynb b/docs/book/programs/gov/hmrc/national-insurance.ipynb
index 8bdb55af3..4108e86fd 100644
--- a/docs/book/programs/gov/hmrc/national-insurance.ipynb
+++ b/docs/book/programs/gov/hmrc/national-insurance.ipynb
@@ -133,8 +133,6 @@
    "source": [
     "# @title\n",
     "import pandas as pd\n",
-    "from tabulate import tabulate\n",
-    "\n",
     "\n",
     "data = {\n",
     "    \"Class\": [\"Class 1\", \"Class 2\", \"Class 4\"],\n",
@@ -1433,11 +1431,12 @@
     }
    ],
    "source": [
-    "from policyengine_uk.system import system\n",
     "import plotly.express as px\n",
     "from policyengine_core.charts import format_fig\n",
     "from policyengine_core.parameters import Parameter\n",
     "\n",
+    "from policyengine_uk.system import system\n",
+    "\n",
     "ni = system.parameters.gov.hmrc.national_insurance\n",
     "\n",
     "threshold_parameters = [\n",
diff --git a/docs/book/programs/gov/hmrc/stamp-duty.ipynb b/docs/book/programs/gov/hmrc/stamp-duty.ipynb
index b7975450b..fe094cbbf 100644
--- a/docs/book/programs/gov/hmrc/stamp-duty.ipynb
+++ b/docs/book/programs/gov/hmrc/stamp-duty.ipynb
@@ -7298,9 +7298,10 @@
     }
    ],
    "source": [
-    "from policyengine_uk.system import system\n",
     "from policyengine_core.charts import format_fig\n",
     "\n",
+    "from policyengine_uk.system import system\n",
+    "\n",
     "sdlt = system.parameters.gov.hmrc.stamp_duty.statistics\n",
     "stats = {\"Year\": [], \"Revenue (£m)\": [], \"Type\": []}\n",
     "# residential corporate\n",
diff --git a/docs/book/programs/gov/ofgem/energy-price-guarantee.ipynb b/docs/book/programs/gov/ofgem/energy-price-guarantee.ipynb
index e23a13d53..a3fde8e5b 100644
--- a/docs/book/programs/gov/ofgem/energy-price-guarantee.ipynb
+++ b/docs/book/programs/gov/ofgem/energy-price-guarantee.ipynb
@@ -1002,9 +1002,10 @@
     }
    ],
    "source": [
-    "from policyengine_uk import CountryTaxBenefitSystem\n",
-    "import plotly.express as px\n",
     "import pandas as pd\n",
+    "import plotly.express as px\n",
+    "\n",
+    "from policyengine_uk import CountryTaxBenefitSystem\n",
     "\n",
     "system = CountryTaxBenefitSystem()\n",
     "ofgem = system.parameters.gov.ofgem\n",
diff --git a/docs/book/programs/gov/revenue_scotland/land-and-buildings-transaction-tax.ipynb b/docs/book/programs/gov/revenue_scotland/land-and-buildings-transaction-tax.ipynb
index 6e6400b9c..5227fbdee 100644
--- a/docs/book/programs/gov/revenue_scotland/land-and-buildings-transaction-tax.ipynb
+++ b/docs/book/programs/gov/revenue_scotland/land-and-buildings-transaction-tax.ipynb
@@ -1171,6 +1171,7 @@
     "import pandas as pd\n",
     "import plotly.express as px\n",
     "from policyengine_core.charts import format_fig\n",
+    "\n",
     "from policyengine_uk import CountryTaxBenefitSystem\n",
     "\n",
     "system = CountryTaxBenefitSystem()\n",
diff --git a/docs/book/programs/gov/wra/land-transaction-tax.ipynb b/docs/book/programs/gov/wra/land-transaction-tax.ipynb
index 80d4549ce..628dc12d3 100644
--- a/docs/book/programs/gov/wra/land-transaction-tax.ipynb
+++ b/docs/book/programs/gov/wra/land-transaction-tax.ipynb
@@ -1114,6 +1114,7 @@
     "import pandas as pd\n",
     "import plotly.express as px\n",
     "from policyengine_core.charts import format_fig\n",
+    "\n",
     "from policyengine_uk import CountryTaxBenefitSystem\n",
     "\n",
     "system = CountryTaxBenefitSystem()\n",
diff --git a/docs/book/validation/student-loan-repayments.ipynb b/docs/book/validation/student-loan-repayments.ipynb
index d6b90f76e..893a5735e 100644
--- a/docs/book/validation/student-loan-repayments.ipynb
+++ b/docs/book/validation/student-loan-repayments.ipynb
@@ -32,9 +32,9 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "from policyengine_uk import Microsimulation\n",
     "import numpy as np\n",
-    "import pandas as pd\n",
+    "\n",
+    "from policyengine_uk import Microsimulation\n",
     "\n",
     "sim = Microsimulation()\n",
     "year = 2025"
diff --git a/docs/book/validation/validation.ipynb b/docs/book/validation/validation.ipynb
index 2e3dc159b..c26ff09e2 100644
--- a/docs/book/validation/validation.ipynb
+++ b/docs/book/validation/validation.ipynb
@@ -1891,10 +1891,10 @@
     "    ]\n",
     "\n",
     "\n",
+    "from policyengine_core.parameters import get_parameter\n",
     "from policyengine_uk.data.datasets.frs.calibration.loss import (\n",
     "    calibration_parameters,\n",
     ")\n",
-    "from policyengine_core.parameters import get_parameter\n",
     "\n",
     "\n",
     "def official_estimate(parameter: str):\n",
@@ -2008,7 +2008,7 @@
     "                )\n",
     "\n",
     "import plotly.express as px\n",
-    "from policyengine_core.charts import format_fig, BLUE_COLOUR_SCALE, GRAY\n",
+    "from policyengine_core.charts import BLUE_COLOUR_SCALE, GRAY, format_fig\n",
     "\n",
     "fig = (\n",
     "    px.bar(\n",
diff --git a/policyengine_uk/__init__.py b/policyengine_uk/__init__.py
index 30f4828b5..e488c3b7d 100644
--- a/policyengine_uk/__init__.py
+++ b/policyengine_uk/__init__.py
@@ -7,13 +7,14 @@
 
 from policyengine_uk import entities
 from policyengine_uk.system import (
+    COUNTRY_DIR,
     CountryTaxBenefitSystem,
     Microsimulation,
     Simulation,
-    COUNTRY_DIR,
     parameters,
     variables,
 )
+
 from .model_api import *
 
 REPO = Path(__file__).parent
diff --git a/policyengine_uk/data/__init__.py b/policyengine_uk/data/__init__.py
index e41a12035..4f7334b88 100644
--- a/policyengine_uk/data/__init__.py
+++ b/policyengine_uk/data/__init__.py
@@ -2,4 +2,5 @@
     UKMultiYearDataset,
     UKSingleYearDataset,
 )
+
 from .filter_dataset import filter_dataset
diff --git a/policyengine_uk/data/dataset_schema.py b/policyengine_uk/data/dataset_schema.py
index d2fa19a74..501e3a8d0 100644
--- a/policyengine_uk/data/dataset_schema.py
+++ b/policyengine_uk/data/dataset_schema.py
@@ -1,11 +1,13 @@
-import pandas as pd
-import numpy as np
 from typing import TYPE_CHECKING
 
+import numpy as np
+import pandas as pd
+
 if TYPE_CHECKING:
     from policyengine_uk import Microsimulation
 
 from pathlib import Path
+
 import h5py
 
 
diff --git a/policyengine_uk/data/economic_assumptions.py b/policyengine_uk/data/economic_assumptions.py
index 9c6d84946..3dd4cc28a 100644
--- a/policyengine_uk/data/economic_assumptions.py
+++ b/policyengine_uk/data/economic_assumptions.py
@@ -1,10 +1,11 @@
-from policyengine_uk.data import UKMultiYearDataset, UKSingleYearDataset
+import logging
+from pathlib import Path
 
+import numpy as np
 import yaml
 from policyengine_core.parameters import ParameterNode
-from pathlib import Path
-import numpy as np
-import logging
+
+from policyengine_uk.data import UKMultiYearDataset, UKSingleYearDataset
 
 # Base year for the FRS dataset - used to calculate age offsets
 _FRS_BASE_YEAR = 2023  # FRS 2023-24 represents calendar year 2024
@@ -55,7 +56,6 @@ def apply_uprating(
     dataset: UKMultiYearDataset,
     tax_benefit_system_parameters: ParameterNode = None,
 ):
-    from policyengine_uk.system import system
 
     # Apply uprating to the dataset.
     dataset = dataset.copy()
diff --git a/policyengine_uk/data/filter_dataset.py b/policyengine_uk/data/filter_dataset.py
index db0b2bafc..ecd2bd595 100644
--- a/policyengine_uk/data/filter_dataset.py
+++ b/policyengine_uk/data/filter_dataset.py
@@ -8,7 +8,6 @@
 def filter_dataset(
     sim: "Microsimulation", household_id: int, year: int = 2026
 ) -> "UKSingleYearDataset":
-    from policyengine_uk import Microsimulation
     from policyengine_uk.data import UKSingleYearDataset
 
     """
diff --git a/policyengine_uk/dynamics/labour_supply.py b/policyengine_uk/dynamics/labour_supply.py
index 43f035847..c9130fdb3 100644
--- a/policyengine_uk/dynamics/labour_supply.py
+++ b/policyengine_uk/dynamics/labour_supply.py
@@ -8,22 +8,21 @@
 Reference: https://obr.uk/docs/dlm_uploads/NICS-Cut-Impact-on-Labour-Supply-Note.pdf
 """
 
+from typing import Optional
+
 import numpy as np
 import pandas as pd
-from policyengine_uk import Simulation
 from microdf import MicroDataFrame
 from pydantic import BaseModel
-from typing import Optional
+
+from policyengine_uk import Simulation
 
 from .progression import (
     calculate_derivative_change,
-    calculate_relative_income_change,
-    calculate_labour_substitution_elasticities,
-    calculate_labour_net_income_elasticities,
     calculate_employment_income_change,
-)
-from .participation import (
-    apply_participation_responses,
+    calculate_labour_net_income_elasticities,
+    calculate_labour_substitution_elasticities,
+    calculate_relative_income_change,
 )
 
 
diff --git a/policyengine_uk/dynamics/participation.py b/policyengine_uk/dynamics/participation.py
index c39d521b9..8708022d3 100644
--- a/policyengine_uk/dynamics/participation.py
+++ b/policyengine_uk/dynamics/participation.py
@@ -9,8 +9,8 @@
 
 import numpy as np
 import pandas as pd
+
 from policyengine_uk import Simulation
-import warnings
 
 
 def calculate_participation_elasticities(
diff --git a/policyengine_uk/dynamics/progression.py b/policyengine_uk/dynamics/progression.py
index 7c4735c2d..94e11ffdb 100644
--- a/policyengine_uk/dynamics/progression.py
+++ b/policyengine_uk/dynamics/progression.py
@@ -9,6 +9,7 @@
 
 import numpy as np
 import pandas as pd
+
 from policyengine_uk import Simulation
 
 
diff --git a/policyengine_uk/model_api.py b/policyengine_uk/model_api.py
index 367801d23..715f76ff5 100644
--- a/policyengine_uk/model_api.py
+++ b/policyengine_uk/model_api.py
@@ -1,7 +1,5 @@
 from policyengine_core.model_api import *
+
 from policyengine_uk.entities import *
-from policyengine_core import periods
-from microdf import MicroSeries, MicroDataFrame
-from policyengine_uk.utils.scenario import Scenario
 
 GBP = "currency-GBP"
diff --git a/policyengine_uk/parameters/gov/contrib/create_private_pension_uprating.py b/policyengine_uk/parameters/gov/contrib/create_private_pension_uprating.py
index c09fbe6b7..079239fa4 100644
--- a/policyengine_uk/parameters/gov/contrib/create_private_pension_uprating.py
+++ b/policyengine_uk/parameters/gov/contrib/create_private_pension_uprating.py
@@ -1,6 +1,6 @@
 from policyengine_core.parameters import (
-    ParameterNode,
     Parameter,
+    ParameterNode,
 )
 
 YEARS = list(range(2020, 2035))
diff --git a/policyengine_uk/parameters/gov/dwp/LHA/__init__.py b/policyengine_uk/parameters/gov/dwp/LHA/__init__.py
index 3d0d3e4eb..5d8f436ba 100644
--- a/policyengine_uk/parameters/gov/dwp/LHA/__init__.py
+++ b/policyengine_uk/parameters/gov/dwp/LHA/__init__.py
@@ -1,4 +1,5 @@
-import pandas as pd
 from pathlib import Path
 
+import pandas as pd
+
 lha_list_of_rents = pd.read_csv(Path(__file__).parent / "lha_list_of_rents.csv.gz")
diff --git a/policyengine_uk/parameters/gov/dwp/state_pension/triple_lock/create_triple_lock.py b/policyengine_uk/parameters/gov/dwp/state_pension/triple_lock/create_triple_lock.py
index 92763ff8b..dc409c921 100644
--- a/policyengine_uk/parameters/gov/dwp/state_pension/triple_lock/create_triple_lock.py
+++ b/policyengine_uk/parameters/gov/dwp/state_pension/triple_lock/create_triple_lock.py
@@ -1,7 +1,6 @@
 from policyengine_core.parameters import (
-    ParameterNode,
     Parameter,
-    get_parameter,
+    ParameterNode,
 )
 
 YEARS = list(range(2022, 2035))
diff --git a/policyengine_uk/parameters/gov/economic_assumptions/create_economic_assumption_indices.py b/policyengine_uk/parameters/gov/economic_assumptions/create_economic_assumption_indices.py
index f87f0b7f5..57f792692 100644
--- a/policyengine_uk/parameters/gov/economic_assumptions/create_economic_assumption_indices.py
+++ b/policyengine_uk/parameters/gov/economic_assumptions/create_economic_assumption_indices.py
@@ -1,7 +1,6 @@
 from policyengine_core.parameters import (
-    ParameterNode,
     Parameter,
-    get_parameter,
+    ParameterNode,
 )
 
 
diff --git a/policyengine_uk/parameters/gov/hmrc/fuel_duty/calculate_fuel_duty_rates.py b/policyengine_uk/parameters/gov/hmrc/fuel_duty/calculate_fuel_duty_rates.py
index 082e6122b..90bb475ef 100644
--- a/policyengine_uk/parameters/gov/hmrc/fuel_duty/calculate_fuel_duty_rates.py
+++ b/policyengine_uk/parameters/gov/hmrc/fuel_duty/calculate_fuel_duty_rates.py
@@ -12,8 +12,8 @@
 
 import argparse
 import re
-from datetime import date
 from calendar import isleap
+from datetime import date
 from pathlib import Path
 
 import yaml
diff --git a/policyengine_uk/reforms/cps/marriage_tax_reforms.py b/policyengine_uk/reforms/cps/marriage_tax_reforms.py
index 98b045fd1..42bfa2384 100644
--- a/policyengine_uk/reforms/cps/marriage_tax_reforms.py
+++ b/policyengine_uk/reforms/cps/marriage_tax_reforms.py
@@ -1,5 +1,6 @@
+from typing import Optional
+
 from policyengine_uk.model_api import *
-from typing import Union, Optional
 
 
 def create_expanded_ma_reform(
diff --git a/policyengine_uk/reforms/reforms.py b/policyengine_uk/reforms/reforms.py
index be00af9a3..a332beaef 100644
--- a/policyengine_uk/reforms/reforms.py
+++ b/policyengine_uk/reforms/reforms.py
@@ -1,12 +1,13 @@
-from .cps import create_marriage_tax_reform
+from policyengine_core import periods
+from policyengine_core.model_api import *
+
 from .conservatives import create_household_based_hitc_reform
+from .cps import create_marriage_tax_reform
 from .policyengine import (
     disable_simulated_benefits,
 )
 from .policyengine.adjust_budgets import adjust_budgets
 from .scotland import create_scottish_child_payment_reform
-from policyengine_core.model_api import *
-from policyengine_core import periods
 
 
 def create_structural_reforms_from_parameters(parameters, period):
diff --git a/policyengine_uk/reforms/scotland/scottish_child_payment_reform.py b/policyengine_uk/reforms/scotland/scottish_child_payment_reform.py
index 44910e585..00d6e8cee 100644
--- a/policyengine_uk/reforms/scotland/scottish_child_payment_reform.py
+++ b/policyengine_uk/reforms/scotland/scottish_child_payment_reform.py
@@ -1,6 +1,7 @@
-from policyengine_uk.model_api import *
 from policyengine_core.periods import period as period_
 
+from policyengine_uk.model_api import *
+
 
 def create_scottish_child_payment_baby_bonus_reform() -> Reform:
     """
diff --git a/policyengine_uk/scenarios/pip_reform.py b/policyengine_uk/scenarios/pip_reform.py
index dd1a0cafa..e6a5d94e3 100644
--- a/policyengine_uk/scenarios/pip_reform.py
+++ b/policyengine_uk/scenarios/pip_reform.py
@@ -1,7 +1,8 @@
-from policyengine_uk.model_api import Scenario
-from policyengine_uk import Simulation
 import numpy as np
 
+from policyengine_uk import Simulation
+from policyengine_uk.model_api import Scenario
+
 
 def modify_simulation(sim: Simulation):
     np.random.seed(42)  # For reproducibility
diff --git a/policyengine_uk/scenarios/reindex_benefit_cap.py b/policyengine_uk/scenarios/reindex_benefit_cap.py
index 8d33eb70a..8eedc7851 100644
--- a/policyengine_uk/scenarios/reindex_benefit_cap.py
+++ b/policyengine_uk/scenarios/reindex_benefit_cap.py
@@ -1,7 +1,8 @@
-from policyengine_uk.model_api import Scenario
-from policyengine_uk import Simulation
 from policyengine_core.parameters import Parameter
 
+from policyengine_uk import Simulation
+from policyengine_uk.model_api import Scenario
+
 
 def index_benefit_cap(simulation: Simulation):
     # Identify benefit cap parameters
diff --git a/policyengine_uk/scenarios/repeal_two_child_limit.py b/policyengine_uk/scenarios/repeal_two_child_limit.py
index 09f9d1e76..95d591b3f 100644
--- a/policyengine_uk/scenarios/repeal_two_child_limit.py
+++ b/policyengine_uk/scenarios/repeal_two_child_limit.py
@@ -1,6 +1,7 @@
-from policyengine_uk.model_api import Scenario
 import numpy as np
 
+from policyengine_uk.model_api import Scenario
+
 repeal_two_child_limit = Scenario(
     parameter_changes={
         "gov.dwp.universal_credit.elements.child.limit.child_count": {
diff --git a/policyengine_uk/scenarios/uc_reform.py b/policyengine_uk/scenarios/uc_reform.py
index cd0f4e3a7..2c5f5710e 100644
--- a/policyengine_uk/scenarios/uc_reform.py
+++ b/policyengine_uk/scenarios/uc_reform.py
@@ -1,7 +1,8 @@
-from policyengine_uk.model_api import Scenario
-from policyengine_uk import Microsimulation
 import numpy as np
 
+from policyengine_uk import Microsimulation
+from policyengine_uk.model_api import Scenario
+
 
 def add_universal_credit_reform(sim: Microsimulation):
     rebalancing = sim.tax_benefit_system.parameters.gov.dwp.universal_credit.rebalancing
diff --git a/policyengine_uk/simulation.py b/policyengine_uk/simulation.py
index 4f6bc1822..c8e384ee3 100644
--- a/policyengine_uk/simulation.py
+++ b/policyengine_uk/simulation.py
@@ -1,15 +1,16 @@
 # Standard library imports
-from typing import Dict, Optional, Union, Type, List
+from typing import Dict, List, Optional, Type, Union
 
 # Third-party imports
 import numpy as np
 import pandas as pd
+from microdf import MicroDataFrame
 
 # PolicyEngine core imports
 from policyengine_core.data import Dataset
 from policyengine_core.enums import Enum as CoreEnum
-from policyengine_core.periods import period as period_
 from policyengine_core.parameters import Parameter
+from policyengine_core.periods import period as period_
 from policyengine_core.reforms import Reform
 from policyengine_core.simulations import Simulation as CoreSimulation
 from policyengine_core.tools.hugging_face import download_huggingface_dataset
@@ -20,17 +21,15 @@
     UKMultiYearDataset,
     UKSingleYearDataset,
 )
-from policyengine_uk.utils.scenario import Scenario
 from policyengine_uk.data.economic_assumptions import (
     extend_single_year_dataset,
 )
-from policyengine_uk.utils.dependencies import get_variable_dependencies
 from policyengine_uk.reforms import create_structural_reforms_from_parameters
+from policyengine_uk.utils.dependencies import get_variable_dependencies
+from policyengine_uk.utils.scenario import Scenario
 
 from .tax_benefit_system import CountryTaxBenefitSystem
 
-from microdf import MicroDataFrame
-
 # Cache for fully-loaded, uprated, enum-pre-encoded multi-year datasets keyed
 # by URL. Avoids repeating HDF5 reading (0.84s), uprating (0.69s) and enum
 # encoding (0.67s) on every Simulation() call after the first.
@@ -253,7 +252,7 @@ def build_from_url(self, url: str) -> None:
             ValueError: If URL is not a HuggingFace URL
         """
         if "hf://" not in url:
-            raise ValueError(f"Non-HuggingFace URLs are currently not supported.")
+            raise ValueError("Non-HuggingFace URLs are currently not supported.")
 
         # Return early from in-memory cache if available: skips HDF5 reading,
         # uprating and enum encoding (~2.2s on the first load).
@@ -580,7 +579,7 @@ def get_variable_dependencies(self, variable_name: str, depth: int = 1):
                         variable, self._example_simulation
                     )
                     self._variable_dependencies[variable] = dependencies
-                except Exception as e:
+                except Exception:
                     self._variable_dependencies[variable] = []
 
         if variable_name not in self._variable_dependencies:
diff --git a/policyengine_uk/system.py b/policyengine_uk/system.py
index 5d926165a..b87e2c5c6 100644
--- a/policyengine_uk/system.py
+++ b/policyengine_uk/system.py
@@ -1,3 +1,3 @@
-from .tax_benefit_system import *
-from .simulation import *
 from .microsimulation import *
+from .simulation import *
+from .tax_benefit_system import *
diff --git a/policyengine_uk/tests/code_health/test_variables.py b/policyengine_uk/tests/code_health/test_variables.py
index 1cda05ae0..340014ab0 100644
--- a/policyengine_uk/tests/code_health/test_variables.py
+++ b/policyengine_uk/tests/code_health/test_variables.py
@@ -1,4 +1,5 @@
 from policyengine_core.model_api import Enum
+
 from policyengine_uk.system import variables as BASELINE_VARIABLES
 
 
@@ -13,7 +14,7 @@ def test_variable_names_match_return_types():
                 assert variable.value_type == bool
             else:
                 assert variable.value_type in (Enum, float, bool, str, int)
-        except Exception as e:
+        except Exception:
             exceptions += [f"{var_name} returns {variable.value_type}"]
     print(
         f"Total variables: {len(BASELINE_VARIABLES)}, variable name violations: {len(exceptions)}."
diff --git a/policyengine_uk/tests/core/test_pandas3_enum_encoding.py b/policyengine_uk/tests/core/test_pandas3_enum_encoding.py
index 871380938..adbeb2153 100644
--- a/policyengine_uk/tests/core/test_pandas3_enum_encoding.py
+++ b/policyengine_uk/tests/core/test_pandas3_enum_encoding.py
@@ -4,10 +4,7 @@
 pandas Series with StringDtype index when encoding enums.
 """
 
-import numpy as np
 import pandas as pd
-import pytest
-
 from policyengine_core.enums import Enum
 
 
diff --git a/policyengine_uk/tests/microsimulation/test_reform_impacts.py b/policyengine_uk/tests/microsimulation/test_reform_impacts.py
index 26561414f..ffce5009b 100644
--- a/policyengine_uk/tests/microsimulation/test_reform_impacts.py
+++ b/policyengine_uk/tests/microsimulation/test_reform_impacts.py
@@ -3,9 +3,11 @@
 This file tests that model changes don't unexpectedly change reform impacts.
 """
 
+from pathlib import Path
+
 import pytest
 import yaml
-from pathlib import Path
+
 from policyengine_uk import Microsimulation
 
 # Load configuration from YAML file
diff --git a/policyengine_uk/tests/microsimulation/test_salary_sacrifice_cap_reform.py b/policyengine_uk/tests/microsimulation/test_salary_sacrifice_cap_reform.py
index 74d9c2a75..b4378e905 100644
--- a/policyengine_uk/tests/microsimulation/test_salary_sacrifice_cap_reform.py
+++ b/policyengine_uk/tests/microsimulation/test_salary_sacrifice_cap_reform.py
@@ -15,9 +15,10 @@
 Reference: https://policyengine.org/uk/research/uk-salary-sacrifice-cap
 """
 
-import pytest
 import numpy as np
 import pandas as pd
+import pytest
+
 from policyengine_uk import Microsimulation
 
 # Policy year when the salary sacrifice cap takes effect
diff --git a/policyengine_uk/tests/microsimulation/update_reform_impacts.py b/policyengine_uk/tests/microsimulation/update_reform_impacts.py
index 5095b4034..e55cd3ace 100644
--- a/policyengine_uk/tests/microsimulation/update_reform_impacts.py
+++ b/policyengine_uk/tests/microsimulation/update_reform_impacts.py
@@ -3,23 +3,24 @@
 This should be run when you want to update the baseline expectations after model changes.
 """
 
-import yaml
-from pathlib import Path
-from policyengine_uk import Microsimulation
 import argparse
+import traceback
 from datetime import datetime
+from pathlib import Path
+
+import yaml
 from rich.console import Console
-from rich.table import Table
+from rich.panel import Panel
 from rich.progress import (
+    BarColumn,
     Progress,
     SpinnerColumn,
-    TextColumn,
-    BarColumn,
     TaskProgressColumn,
+    TextColumn,
 )
-from rich.panel import Panel
-from rich import print as rprint
-import traceback
+from rich.table import Table
+
+from policyengine_uk import Microsimulation
 
 baseline = Microsimulation()
 
diff --git a/policyengine_uk/tests/test_behavioral_responses.py b/policyengine_uk/tests/test_behavioral_responses.py
index 9dd869cc0..1aac0010c 100644
--- a/policyengine_uk/tests/test_behavioral_responses.py
+++ b/policyengine_uk/tests/test_behavioral_responses.py
@@ -10,9 +10,11 @@
 """
 
 import os
+from pathlib import Path
+
 import pytest
 import yaml
-from pathlib import Path
+
 from policyengine_uk import Microsimulation
 from policyengine_uk.model_api import Scenario
 
diff --git a/policyengine_uk/tests/test_deterministic_variables.py b/policyengine_uk/tests/test_deterministic_variables.py
index b76de48ad..204e797a0 100644
--- a/policyengine_uk/tests/test_deterministic_variables.py
+++ b/policyengine_uk/tests/test_deterministic_variables.py
@@ -6,7 +6,6 @@
 3. Produce deterministic results
 """
 
-import pytest
 from policyengine_uk import Simulation
 
 
diff --git a/policyengine_uk/tests/test_fiscal_year_parameters.py b/policyengine_uk/tests/test_fiscal_year_parameters.py
index 08992a266..906754fae 100644
--- a/policyengine_uk/tests/test_fiscal_year_parameters.py
+++ b/policyengine_uk/tests/test_fiscal_year_parameters.py
@@ -14,6 +14,7 @@
 """
 
 import pytest
+
 from policyengine_uk import CountryTaxBenefitSystem
 
 
diff --git a/policyengine_uk/tests/test_parameter_metadata.py b/policyengine_uk/tests/test_parameter_metadata.py
index 7a85a4de5..97ffc87a4 100644
--- a/policyengine_uk/tests/test_parameter_metadata.py
+++ b/policyengine_uk/tests/test_parameter_metadata.py
@@ -1,6 +1,6 @@
-from policyengine_uk.system import system
 from policyengine_core.model_api import Parameter
-import pytest
+
+from policyengine_uk.system import system
 
 parameters = list(
     filter(
diff --git a/policyengine_uk/utils/compare.py b/policyengine_uk/utils/compare.py
index e883e4bc2..aa92231fb 100644
--- a/policyengine_uk/utils/compare.py
+++ b/policyengine_uk/utils/compare.py
@@ -1,6 +1,7 @@
-import pandas as pd
 from typing import TYPE_CHECKING
 
+import pandas as pd
+
 if TYPE_CHECKING:
     from policyengine_uk.simulation import Microsimulation
 
diff --git a/policyengine_uk/utils/create_ahc_deflator.py b/policyengine_uk/utils/create_ahc_deflator.py
index 0d0e90df3..f240d08cc 100644
--- a/policyengine_uk/utils/create_ahc_deflator.py
+++ b/policyengine_uk/utils/create_ahc_deflator.py
@@ -1,5 +1,5 @@
-import pandas as pd
 import numpy as np
+import pandas as pd
 
 from policyengine_uk.system import system
 
diff --git a/policyengine_uk/utils/dependencies.py b/policyengine_uk/utils/dependencies.py
index 1d433d969..047280d26 100644
--- a/policyengine_uk/utils/dependencies.py
+++ b/policyengine_uk/utils/dependencies.py
@@ -1,6 +1,5 @@
 import re
-from policyengine_uk.system import system
-import plotly.express as px
+
 import pandas as pd
 from plotly import graph_objects as go
 
diff --git a/policyengine_uk/utils/parameters.py b/policyengine_uk/utils/parameters.py
index 8eb08a2b0..92f9ebfe5 100644
--- a/policyengine_uk/utils/parameters.py
+++ b/policyengine_uk/utils/parameters.py
@@ -1,5 +1,5 @@
-from policyengine_core.model_api import *
 from policyengine_core import periods
+from policyengine_core.model_api import *
 
 
 def str_to_instant(s):
diff --git a/policyengine_uk/utils/scenario.py b/policyengine_uk/utils/scenario.py
index d251699af..bb7916f74 100644
--- a/policyengine_uk/utils/scenario.py
+++ b/policyengine_uk/utils/scenario.py
@@ -1,8 +1,9 @@
-from pydantic import BaseModel
-from typing import Optional, Callable, Dict, Type, Union
-from policyengine_core.simulations import Simulation
+from typing import Callable, Dict, Optional, Type, Union
+
+from policyengine_core.periods import instant, period
 from policyengine_core.reforms import Reform
-from policyengine_core.periods import period, instant
+from policyengine_core.simulations import Simulation
+from pydantic import BaseModel
 
 
 class Scenario(BaseModel):
diff --git a/policyengine_uk/utils/solve_private_school_attendance_factor.py b/policyengine_uk/utils/solve_private_school_attendance_factor.py
index 47923382d..f23d67160 100644
--- a/policyengine_uk/utils/solve_private_school_attendance_factor.py
+++ b/policyengine_uk/utils/solve_private_school_attendance_factor.py
@@ -1,7 +1,7 @@
-from policyengine_uk import Microsimulation
-from policyengine_core.reforms import Reform
 from tqdm import tqdm
 
+from policyengine_uk import Microsimulation
+
 # Initialize variables to track the best private_school_factor and its result
 best_factor = None
 smallest_difference = float("inf")
diff --git a/policyengine_uk/utils/water/forecast_water_bills.py b/policyengine_uk/utils/water/forecast_water_bills.py
index 52ed47a97..e8b44de2d 100644
--- a/policyengine_uk/utils/water/forecast_water_bills.py
+++ b/policyengine_uk/utils/water/forecast_water_bills.py
@@ -1,5 +1,6 @@
-import pandas as pd
 from pathlib import Path
+
+import pandas as pd
 from microdf import MicroDataFrame
 
 
diff --git a/policyengine_uk/variables/contrib/ubi_center/basic_income/bi_household_phaseout.py b/policyengine_uk/variables/contrib/ubi_center/basic_income/bi_household_phaseout.py
index 1edff6855..913e0b5ec 100644
--- a/policyengine_uk/variables/contrib/ubi_center/basic_income/bi_household_phaseout.py
+++ b/policyengine_uk/variables/contrib/ubi_center/basic_income/bi_household_phaseout.py
@@ -1,6 +1,7 @@
-from policyengine_uk.model_api import *
 import warnings
 
+from policyengine_uk.model_api import *
+
 
 class bi_household_phaseout(Variable):
     label = "Basic income phase-out (household)"
diff --git a/policyengine_uk/variables/contrib/ubi_center/basic_income/bi_individual_phaseout.py b/policyengine_uk/variables/contrib/ubi_center/basic_income/bi_individual_phaseout.py
index 41d287e60..39cfe0e84 100644
--- a/policyengine_uk/variables/contrib/ubi_center/basic_income/bi_individual_phaseout.py
+++ b/policyengine_uk/variables/contrib/ubi_center/basic_income/bi_individual_phaseout.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import warnings
 
 
 class bi_individual_phaseout(Variable):
diff --git a/policyengine_uk/variables/gov/dwp/BRMA_LHA_rate.py b/policyengine_uk/variables/gov/dwp/BRMA_LHA_rate.py
index 4b4d9222c..72a31f857 100644
--- a/policyengine_uk/variables/gov/dwp/BRMA_LHA_rate.py
+++ b/policyengine_uk/variables/gov/dwp/BRMA_LHA_rate.py
@@ -1,7 +1,9 @@
-from policyengine_uk.model_api import *
-import pandas as pd
 import warnings
+
+import pandas as pd
 from policyengine_core.model_api import *
+
+from policyengine_uk.model_api import *
 from policyengine_uk.variables.gov.dwp.LHA_category import (
     find_freeze_start,
     time_shift_dataset,
diff --git a/policyengine_uk/variables/gov/dwp/LHA_allowed_bedrooms.py b/policyengine_uk/variables/gov/dwp/LHA_allowed_bedrooms.py
index 9dff0c03c..ae7f4bc28 100644
--- a/policyengine_uk/variables/gov/dwp/LHA_allowed_bedrooms.py
+++ b/policyengine_uk/variables/gov/dwp/LHA_allowed_bedrooms.py
@@ -1,8 +1,9 @@
-from policyengine_uk.model_api import *
-import pandas as pd
 import warnings
+
 from policyengine_core.model_api import *
 
+from policyengine_uk.model_api import *
+
 warnings.filterwarnings("ignore")
 
 
diff --git a/policyengine_uk/variables/gov/dwp/LHA_cap.py b/policyengine_uk/variables/gov/dwp/LHA_cap.py
index d7139422c..06c030116 100644
--- a/policyengine_uk/variables/gov/dwp/LHA_cap.py
+++ b/policyengine_uk/variables/gov/dwp/LHA_cap.py
@@ -1,8 +1,9 @@
-from policyengine_uk.model_api import *
-import pandas as pd
 import warnings
+
 from policyengine_core.model_api import *
 
+from policyengine_uk.model_api import *
+
 warnings.filterwarnings("ignore")
 
 
diff --git a/policyengine_uk/variables/gov/dwp/LHA_category.py b/policyengine_uk/variables/gov/dwp/LHA_category.py
index 093112d4b..2688c01b7 100644
--- a/policyengine_uk/variables/gov/dwp/LHA_category.py
+++ b/policyengine_uk/variables/gov/dwp/LHA_category.py
@@ -1,8 +1,10 @@
-from policyengine_uk.model_api import *
-import pandas as pd
 import warnings
+
+import pandas as pd
 from policyengine_core.model_api import *
 
+from policyengine_uk.model_api import *
+
 warnings.filterwarnings("ignore")
 
 
diff --git a/policyengine_uk/variables/gov/dwp/LHA_eligible.py b/policyengine_uk/variables/gov/dwp/LHA_eligible.py
index 008e3f822..d2b99124f 100644
--- a/policyengine_uk/variables/gov/dwp/LHA_eligible.py
+++ b/policyengine_uk/variables/gov/dwp/LHA_eligible.py
@@ -1,8 +1,9 @@
-from policyengine_uk.model_api import *
-import pandas as pd
 import warnings
+
 from policyengine_core.model_api import *
 
+from policyengine_uk.model_api import *
+
 warnings.filterwarnings("ignore")
 
 
diff --git a/policyengine_uk/variables/gov/dwp/pip/pip_dl_reported.py b/policyengine_uk/variables/gov/dwp/pip/pip_dl_reported.py
index 02ff3277a..4aa3d01cc 100644
--- a/policyengine_uk/variables/gov/dwp/pip/pip_dl_reported.py
+++ b/policyengine_uk/variables/gov/dwp/pip/pip_dl_reported.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.gov.dwp.pip.pip import PIPCategory
 
 
 class pip_dl_reported(Variable):
diff --git a/policyengine_uk/variables/gov/dwp/pip/pip_m_reported.py b/policyengine_uk/variables/gov/dwp/pip/pip_m_reported.py
index bcff89e9d..0fbf6e8a5 100644
--- a/policyengine_uk/variables/gov/dwp/pip/pip_m_reported.py
+++ b/policyengine_uk/variables/gov/dwp/pip/pip_m_reported.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.gov.dwp.pip.pip import PIPCategory
 
 
 class pip_m_reported(Variable):
diff --git a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/adult_index_cg.py b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/adult_index_cg.py
index 3cd2f2d84..95a1d13e4 100644
--- a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/adult_index_cg.py
+++ b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/adult_index_cg.py
@@ -1,6 +1,7 @@
-from policyengine_uk.model_api import *
 from policyengine_core.simulations import *
 
+from policyengine_uk.model_api import *
+
 
 class adult_index_cg(Variable):
     value_type = int
diff --git a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_before_response.py b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_before_response.py
index 45873686f..757f5b22e 100644
--- a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_before_response.py
+++ b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_before_response.py
@@ -1,6 +1,7 @@
-from policyengine_uk.model_api import *
 from policyengine_core.simulations import *
 
+from policyengine_uk.model_api import *
+
 
 class capital_gains_before_response(Variable):
     label = "capital gains before responses"
diff --git a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_behavioural_response.py b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_behavioural_response.py
index 40829f155..1dee2314d 100644
--- a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_behavioural_response.py
+++ b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_behavioural_response.py
@@ -1,6 +1,7 @@
-from policyengine_uk.model_api import *
 from policyengine_core.simulations import *
 
+from policyengine_uk.model_api import *
+
 
 class capital_gains_behavioural_response(Variable):
     value_type = float
diff --git a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_elasticity.py b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_elasticity.py
index 95b98b9d3..1718852d4 100644
--- a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_elasticity.py
+++ b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_elasticity.py
@@ -1,6 +1,7 @@
-from policyengine_uk.model_api import *
 from policyengine_core.simulations import *
 
+from policyengine_uk.model_api import *
+
 
 class capital_gains_elasticity(Variable):
     value_type = float
diff --git a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_tax.py b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_tax.py
index 0538256d7..4840764d7 100644
--- a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_tax.py
+++ b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/capital_gains_tax.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_core.holders import Holder
 
 
 class capital_gains_tax(Variable):
diff --git a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/marginal_tax_rate_on_capital_gains.py b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/marginal_tax_rate_on_capital_gains.py
index e011505a3..8ffa3a97a 100644
--- a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/marginal_tax_rate_on_capital_gains.py
+++ b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/marginal_tax_rate_on_capital_gains.py
@@ -1,6 +1,7 @@
-from policyengine_uk.model_api import *
 from policyengine_core.simulations import *
 
+from policyengine_uk.model_api import *
+
 
 class marginal_tax_rate_on_capital_gains(Variable):
     label = "capital gains marginal tax rate"
diff --git a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/relative_capital_gains_mtr_change.py b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/relative_capital_gains_mtr_change.py
index 4cef0119d..0f68712a6 100644
--- a/policyengine_uk/variables/gov/hmrc/capital_gains_tax/relative_capital_gains_mtr_change.py
+++ b/policyengine_uk/variables/gov/hmrc/capital_gains_tax/relative_capital_gains_mtr_change.py
@@ -1,6 +1,7 @@
-from policyengine_uk.model_api import *
 from policyengine_core.simulations import *
 
+from policyengine_uk.model_api import *
+
 
 class relative_capital_gains_mtr_change(Variable):
     value_type = float
diff --git a/policyengine_uk/variables/gov/hmrc/income_tax/allowances/meets_marriage_allowance_income_conditions.py b/policyengine_uk/variables/gov/hmrc/income_tax/allowances/meets_marriage_allowance_income_conditions.py
index 45c9204c1..69a48f84f 100644
--- a/policyengine_uk/variables/gov/hmrc/income_tax/allowances/meets_marriage_allowance_income_conditions.py
+++ b/policyengine_uk/variables/gov/hmrc/income_tax/allowances/meets_marriage_allowance_income_conditions.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from numpy import ceil
 
 
 class meets_marriage_allowance_income_conditions(Variable):
diff --git a/policyengine_uk/variables/gov/hmrc/income_tax/allowances/partners_unused_personal_allowance.py b/policyengine_uk/variables/gov/hmrc/income_tax/allowances/partners_unused_personal_allowance.py
index e9c8d41e8..0f14adde7 100644
--- a/policyengine_uk/variables/gov/hmrc/income_tax/allowances/partners_unused_personal_allowance.py
+++ b/policyengine_uk/variables/gov/hmrc/income_tax/allowances/partners_unused_personal_allowance.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from numpy import ceil
 
 
 class partners_unused_personal_allowance(Variable):
diff --git a/policyengine_uk/variables/gov/hmrc/income_tax/allowances/unused_personal_allowance.py b/policyengine_uk/variables/gov/hmrc/income_tax/allowances/unused_personal_allowance.py
index 4257638e6..fb3542c0a 100644
--- a/policyengine_uk/variables/gov/hmrc/income_tax/allowances/unused_personal_allowance.py
+++ b/policyengine_uk/variables/gov/hmrc/income_tax/allowances/unused_personal_allowance.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from numpy import ceil
 
 
 class unused_personal_allowance(Variable):
diff --git a/policyengine_uk/variables/gov/hmrc/student_loans/plan_2_interest_rate.py b/policyengine_uk/variables/gov/hmrc/student_loans/plan_2_interest_rate.py
index fe52b5f26..caf076e51 100644
--- a/policyengine_uk/variables/gov/hmrc/student_loans/plan_2_interest_rate.py
+++ b/policyengine_uk/variables/gov/hmrc/student_loans/plan_2_interest_rate.py
@@ -1,6 +1,7 @@
-from policyengine_uk.model_api import *
 import numpy as np
 
+from policyengine_uk.model_api import *
+
 
 class plan_2_interest_rate(Variable):
     value_type = float
diff --git a/policyengine_uk/variables/household/BRMA.py b/policyengine_uk/variables/household/BRMA.py
index ec0b8b422..8e249525d 100644
--- a/policyengine_uk/variables/household/BRMA.py
+++ b/policyengine_uk/variables/household/BRMA.py
@@ -1,8 +1,5 @@
 from policyengine_uk.model_api import *
 from policyengine_uk.variables.household.demographic.locations import BRMAName
-from policyengine_uk.variables.household.demographic.geography import Region
-import pandas as pd
-import numpy as np
 
 
 class brma(Variable):
diff --git a/policyengine_uk/variables/household/demographic/accommodation_type.py b/policyengine_uk/variables/household/demographic/accommodation_type.py
index 9beb07cd1..e8fe83c27 100644
--- a/policyengine_uk/variables/household/demographic/accommodation_type.py
+++ b/policyengine_uk/variables/household/demographic/accommodation_type.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.household.demographic.geography import Region
 
 
 class AccommodationType(Enum):
diff --git a/policyengine_uk/variables/household/demographic/adult_index.py b/policyengine_uk/variables/household/demographic/adult_index.py
index c2ae19384..28dd6d7b2 100644
--- a/policyengine_uk/variables/household/demographic/adult_index.py
+++ b/policyengine_uk/variables/household/demographic/adult_index.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class adult_index(Variable):
diff --git a/policyengine_uk/variables/household/demographic/age_18_64.py b/policyengine_uk/variables/household/demographic/age_18_64.py
index 26942dc67..c9ee5bda9 100644
--- a/policyengine_uk/variables/household/demographic/age_18_64.py
+++ b/policyengine_uk/variables/household/demographic/age_18_64.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class age_18_64(Variable):
diff --git a/policyengine_uk/variables/household/demographic/age_over_64.py b/policyengine_uk/variables/household/demographic/age_over_64.py
index fa341df5f..c1607d341 100644
--- a/policyengine_uk/variables/household/demographic/age_over_64.py
+++ b/policyengine_uk/variables/household/demographic/age_over_64.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class age_over_64(Variable):
diff --git a/policyengine_uk/variables/household/demographic/age_under_18.py b/policyengine_uk/variables/household/demographic/age_under_18.py
index 8d8ee1acd..da030da93 100644
--- a/policyengine_uk/variables/household/demographic/age_under_18.py
+++ b/policyengine_uk/variables/household/demographic/age_under_18.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class age_under_18(Variable):
diff --git a/policyengine_uk/variables/household/demographic/birth_year.py b/policyengine_uk/variables/household/demographic/birth_year.py
index f555e29c1..c00a25190 100644
--- a/policyengine_uk/variables/household/demographic/birth_year.py
+++ b/policyengine_uk/variables/household/demographic/birth_year.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class birth_year(Variable):
diff --git a/policyengine_uk/variables/household/demographic/child_index.py b/policyengine_uk/variables/household/demographic/child_index.py
index a3b038330..42a10ba7c 100644
--- a/policyengine_uk/variables/household/demographic/child_index.py
+++ b/policyengine_uk/variables/household/demographic/child_index.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class child_index(Variable):
diff --git a/policyengine_uk/variables/household/demographic/current_education.py b/policyengine_uk/variables/household/demographic/current_education.py
index e11d2846b..fde8cf97b 100644
--- a/policyengine_uk/variables/household/demographic/current_education.py
+++ b/policyengine_uk/variables/household/demographic/current_education.py
@@ -2,7 +2,6 @@
 from policyengine_uk.variables.household.demographic.highest_education import (
     EducationType,
 )
-import pandas as pd
 
 
 class current_education(Variable):
diff --git a/policyengine_uk/variables/household/demographic/gender.py b/policyengine_uk/variables/household/demographic/gender.py
index 6cda88702..af53e9fe3 100644
--- a/policyengine_uk/variables/household/demographic/gender.py
+++ b/policyengine_uk/variables/household/demographic/gender.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class Gender(Enum):
diff --git a/policyengine_uk/variables/household/demographic/highest_education.py b/policyengine_uk/variables/household/demographic/highest_education.py
index 4bd7efd05..abc630b60 100644
--- a/policyengine_uk/variables/household/demographic/highest_education.py
+++ b/policyengine_uk/variables/household/demographic/highest_education.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class EducationType(Enum):
diff --git a/policyengine_uk/variables/household/demographic/household_count_people.py b/policyengine_uk/variables/household/demographic/household_count_people.py
index b2bb970a8..172539714 100644
--- a/policyengine_uk/variables/household/demographic/household_count_people.py
+++ b/policyengine_uk/variables/household/demographic/household_count_people.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.household.demographic.geography import Region
 
 
 class household_count_people(Variable):
diff --git a/policyengine_uk/variables/household/demographic/household_equivalisation_ahc.py b/policyengine_uk/variables/household/demographic/household_equivalisation_ahc.py
index 4fbfb5991..97b9cf79d 100644
--- a/policyengine_uk/variables/household/demographic/household_equivalisation_ahc.py
+++ b/policyengine_uk/variables/household/demographic/household_equivalisation_ahc.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.household.demographic.geography import Region
 
 
 class household_equivalisation_ahc(Variable):
diff --git a/policyengine_uk/variables/household/demographic/household_equivalisation_bhc.py b/policyengine_uk/variables/household/demographic/household_equivalisation_bhc.py
index 48a1bbf51..8eba98673 100644
--- a/policyengine_uk/variables/household/demographic/household_equivalisation_bhc.py
+++ b/policyengine_uk/variables/household/demographic/household_equivalisation_bhc.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.household.demographic.geography import Region
 
 
 class household_equivalisation_bhc(Variable):
diff --git a/policyengine_uk/variables/household/demographic/household_id.py b/policyengine_uk/variables/household/demographic/household_id.py
index 398a34b8c..549acf27b 100644
--- a/policyengine_uk/variables/household/demographic/household_id.py
+++ b/policyengine_uk/variables/household/demographic/household_id.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.household.demographic.geography import Region
 
 
 class household_id(Variable):
diff --git a/policyengine_uk/variables/household/demographic/household_num_benunits.py b/policyengine_uk/variables/household/demographic/household_num_benunits.py
index 5c5a0b174..2a8d40af9 100644
--- a/policyengine_uk/variables/household/demographic/household_num_benunits.py
+++ b/policyengine_uk/variables/household/demographic/household_num_benunits.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.household.demographic.geography import Region
 
 
 class household_num_benunits(Variable):
diff --git a/policyengine_uk/variables/household/demographic/household_weight.py b/policyengine_uk/variables/household/demographic/household_weight.py
index 1a40c0c9c..e60aad88c 100644
--- a/policyengine_uk/variables/household/demographic/household_weight.py
+++ b/policyengine_uk/variables/household/demographic/household_weight.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.household.demographic.geography import Region
 
 
 class household_weight(Variable):
diff --git a/policyengine_uk/variables/household/demographic/households.py b/policyengine_uk/variables/household/demographic/households.py
index ba0197b04..ec4e67457 100644
--- a/policyengine_uk/variables/household/demographic/households.py
+++ b/policyengine_uk/variables/household/demographic/households.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.household.demographic.geography import Region
 
 
 class households(Variable):
diff --git a/policyengine_uk/variables/household/demographic/in_FE.py b/policyengine_uk/variables/household/demographic/in_FE.py
index 54bae4671..3d04e68ad 100644
--- a/policyengine_uk/variables/household/demographic/in_FE.py
+++ b/policyengine_uk/variables/household/demographic/in_FE.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class in_FE(Variable):
diff --git a/policyengine_uk/variables/household/demographic/in_HE.py b/policyengine_uk/variables/household/demographic/in_HE.py
index 47240bb29..95567920a 100644
--- a/policyengine_uk/variables/household/demographic/in_HE.py
+++ b/policyengine_uk/variables/household/demographic/in_HE.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class in_HE(Variable):
diff --git a/policyengine_uk/variables/household/demographic/in_social_housing.py b/policyengine_uk/variables/household/demographic/in_social_housing.py
index f33c2e768..38ea24813 100644
--- a/policyengine_uk/variables/household/demographic/in_social_housing.py
+++ b/policyengine_uk/variables/household/demographic/in_social_housing.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class in_social_housing(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_WA_adult.py b/policyengine_uk/variables/household/demographic/is_WA_adult.py
index 8db33a6db..0d1a0e368 100644
--- a/policyengine_uk/variables/household/demographic/is_WA_adult.py
+++ b/policyengine_uk/variables/household/demographic/is_WA_adult.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class is_WA_adult(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_adult.py b/policyengine_uk/variables/household/demographic/is_adult.py
index 29bb92d53..7e64b45df 100644
--- a/policyengine_uk/variables/household/demographic/is_adult.py
+++ b/policyengine_uk/variables/household/demographic/is_adult.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class is_adult(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_benunit_eldest_child.py b/policyengine_uk/variables/household/demographic/is_benunit_eldest_child.py
index 58e883aab..f17ac1c8d 100644
--- a/policyengine_uk/variables/household/demographic/is_benunit_eldest_child.py
+++ b/policyengine_uk/variables/household/demographic/is_benunit_eldest_child.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class is_benunit_eldest_child(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_benunit_head.py b/policyengine_uk/variables/household/demographic/is_benunit_head.py
index 4ed35a0dc..2bfd103b5 100644
--- a/policyengine_uk/variables/household/demographic/is_benunit_head.py
+++ b/policyengine_uk/variables/household/demographic/is_benunit_head.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class is_benunit_head(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_child.py b/policyengine_uk/variables/household/demographic/is_child.py
index 675c320d2..9432164ac 100644
--- a/policyengine_uk/variables/household/demographic/is_child.py
+++ b/policyengine_uk/variables/household/demographic/is_child.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class is_child(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_eldest_child.py b/policyengine_uk/variables/household/demographic/is_eldest_child.py
index 91a13a0e0..d8a3024cf 100644
--- a/policyengine_uk/variables/household/demographic/is_eldest_child.py
+++ b/policyengine_uk/variables/household/demographic/is_eldest_child.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class is_eldest_child(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_female.py b/policyengine_uk/variables/household/demographic/is_female.py
index 23abd522c..e1335b9ee 100644
--- a/policyengine_uk/variables/household/demographic/is_female.py
+++ b/policyengine_uk/variables/household/demographic/is_female.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class is_female(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_household_head.py b/policyengine_uk/variables/household/demographic/is_household_head.py
index 44cc52da9..de2f137ba 100644
--- a/policyengine_uk/variables/household/demographic/is_household_head.py
+++ b/policyengine_uk/variables/household/demographic/is_household_head.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class is_household_head(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_male.py b/policyengine_uk/variables/household/demographic/is_male.py
index 364ba86de..fb2e13c6e 100644
--- a/policyengine_uk/variables/household/demographic/is_male.py
+++ b/policyengine_uk/variables/household/demographic/is_male.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class is_male(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_older_child.py b/policyengine_uk/variables/household/demographic/is_older_child.py
index a7555133f..663416f35 100644
--- a/policyengine_uk/variables/household/demographic/is_older_child.py
+++ b/policyengine_uk/variables/household/demographic/is_older_child.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class is_older_child(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_renting.py b/policyengine_uk/variables/household/demographic/is_renting.py
index 150f134c6..0308d92b0 100644
--- a/policyengine_uk/variables/household/demographic/is_renting.py
+++ b/policyengine_uk/variables/household/demographic/is_renting.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.household.demographic.geography import Region
 
 
 class is_renting(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_shared_accommodation.py b/policyengine_uk/variables/household/demographic/is_shared_accommodation.py
index 69f8bd4dd..a88d9fba5 100644
--- a/policyengine_uk/variables/household/demographic/is_shared_accommodation.py
+++ b/policyengine_uk/variables/household/demographic/is_shared_accommodation.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.household.demographic.geography import Region
 
 
 class is_shared_accommodation(Variable):
diff --git a/policyengine_uk/variables/household/demographic/is_young_child.py b/policyengine_uk/variables/household/demographic/is_young_child.py
index a4708d441..cf12f38ba 100644
--- a/policyengine_uk/variables/household/demographic/is_young_child.py
+++ b/policyengine_uk/variables/household/demographic/is_young_child.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class is_young_child(Variable):
diff --git a/policyengine_uk/variables/household/demographic/marital_status.py b/policyengine_uk/variables/household/demographic/marital_status.py
index e70c06faf..8ebfbf84e 100644
--- a/policyengine_uk/variables/household/demographic/marital_status.py
+++ b/policyengine_uk/variables/household/demographic/marital_status.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class MaritalStatus(Enum):
diff --git a/policyengine_uk/variables/household/demographic/num_bedrooms.py b/policyengine_uk/variables/household/demographic/num_bedrooms.py
index d30aff8b2..fe6531903 100644
--- a/policyengine_uk/variables/household/demographic/num_bedrooms.py
+++ b/policyengine_uk/variables/household/demographic/num_bedrooms.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.household.demographic.geography import Region
 
 
 class num_bedrooms(Variable):
diff --git a/policyengine_uk/variables/household/demographic/over_16.py b/policyengine_uk/variables/household/demographic/over_16.py
index 7890afbeb..6681aacb2 100644
--- a/policyengine_uk/variables/household/demographic/over_16.py
+++ b/policyengine_uk/variables/household/demographic/over_16.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class over_16(Variable):
diff --git a/policyengine_uk/variables/household/demographic/people.py b/policyengine_uk/variables/household/demographic/people.py
index 875ab9394..6a8cac024 100644
--- a/policyengine_uk/variables/household/demographic/people.py
+++ b/policyengine_uk/variables/household/demographic/people.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class people(Variable):
diff --git a/policyengine_uk/variables/household/demographic/person_id.py b/policyengine_uk/variables/household/demographic/person_id.py
index b10442bb3..b0bc7ff0c 100644
--- a/policyengine_uk/variables/household/demographic/person_id.py
+++ b/policyengine_uk/variables/household/demographic/person_id.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class person_id(Variable):
diff --git a/policyengine_uk/variables/household/demographic/person_weight.py b/policyengine_uk/variables/household/demographic/person_weight.py
index 05d159156..9e5ff67dd 100644
--- a/policyengine_uk/variables/household/demographic/person_weight.py
+++ b/policyengine_uk/variables/household/demographic/person_weight.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class person_weight(Variable):
diff --git a/policyengine_uk/variables/household/demographic/raw_person_weight.py b/policyengine_uk/variables/household/demographic/raw_person_weight.py
index dde045360..7c0678d53 100644
--- a/policyengine_uk/variables/household/demographic/raw_person_weight.py
+++ b/policyengine_uk/variables/household/demographic/raw_person_weight.py
@@ -1,5 +1,4 @@
 from policyengine_uk.model_api import *
-import pandas as pd
 
 
 class raw_person_weight(Variable):
diff --git a/policyengine_uk/variables/household/income/base_net_income.py b/policyengine_uk/variables/household/income/base_net_income.py
index 51ee47226..58c7ab82a 100644
--- a/policyengine_uk/variables/household/income/base_net_income.py
+++ b/policyengine_uk/variables/household/income/base_net_income.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class base_net_income(Variable):
diff --git a/policyengine_uk/variables/household/income/capital_gains.py b/policyengine_uk/variables/household/income/capital_gains.py
index 19331dd02..d65d5517c 100644
--- a/policyengine_uk/variables/household/income/capital_gains.py
+++ b/policyengine_uk/variables/household/income/capital_gains.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class capital_gains(Variable):
diff --git a/policyengine_uk/variables/household/income/capital_income.py b/policyengine_uk/variables/household/income/capital_income.py
index 91aa83efb..012785208 100644
--- a/policyengine_uk/variables/household/income/capital_income.py
+++ b/policyengine_uk/variables/household/income/capital_income.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class capital_income(Variable):
diff --git a/policyengine_uk/variables/household/income/earned_income.py b/policyengine_uk/variables/household/income/earned_income.py
index 72a066f8f..52bee1515 100644
--- a/policyengine_uk/variables/household/income/earned_income.py
+++ b/policyengine_uk/variables/household/income/earned_income.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class earned_income(Variable):
diff --git a/policyengine_uk/variables/household/income/employment_status.py b/policyengine_uk/variables/household/income/employment_status.py
index 2b3d06941..938e38314 100644
--- a/policyengine_uk/variables/household/income/employment_status.py
+++ b/policyengine_uk/variables/household/income/employment_status.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class EmploymentStatus(Enum):
diff --git a/policyengine_uk/variables/household/income/equiv_hbai_household_net_income.py b/policyengine_uk/variables/household/income/equiv_hbai_household_net_income.py
index e3f6253bd..7a9d9e1fa 100644
--- a/policyengine_uk/variables/household/income/equiv_hbai_household_net_income.py
+++ b/policyengine_uk/variables/household/income/equiv_hbai_household_net_income.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class equiv_hbai_household_net_income(Variable):
diff --git a/policyengine_uk/variables/household/income/equiv_hbai_household_net_income_ahc.py b/policyengine_uk/variables/household/income/equiv_hbai_household_net_income_ahc.py
index ddb760ebe..91169aa9c 100644
--- a/policyengine_uk/variables/household/income/equiv_hbai_household_net_income_ahc.py
+++ b/policyengine_uk/variables/household/income/equiv_hbai_household_net_income_ahc.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class equiv_hbai_household_net_income_ahc(Variable):
diff --git a/policyengine_uk/variables/household/income/equiv_household_net_income.py b/policyengine_uk/variables/household/income/equiv_household_net_income.py
index 35c75b016..0af185c87 100644
--- a/policyengine_uk/variables/household/income/equiv_household_net_income.py
+++ b/policyengine_uk/variables/household/income/equiv_household_net_income.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class equiv_household_net_income(Variable):
diff --git a/policyengine_uk/variables/household/income/hbai_household_net_income.py b/policyengine_uk/variables/household/income/hbai_household_net_income.py
index 78c890db0..2ad8265cc 100644
--- a/policyengine_uk/variables/household/income/hbai_household_net_income.py
+++ b/policyengine_uk/variables/household/income/hbai_household_net_income.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class hbai_household_net_income(Variable):
diff --git a/policyengine_uk/variables/household/income/hbai_household_net_income_ahc.py b/policyengine_uk/variables/household/income/hbai_household_net_income_ahc.py
index f1116ac76..46aa526f2 100644
--- a/policyengine_uk/variables/household/income/hbai_household_net_income_ahc.py
+++ b/policyengine_uk/variables/household/income/hbai_household_net_income_ahc.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class hbai_household_net_income_ahc(Variable):
diff --git a/policyengine_uk/variables/household/income/hours_worked.py b/policyengine_uk/variables/household/income/hours_worked.py
index 403447d8f..301982ddc 100644
--- a/policyengine_uk/variables/household/income/hours_worked.py
+++ b/policyengine_uk/variables/household/income/hours_worked.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class hours_worked(Variable):
diff --git a/policyengine_uk/variables/household/income/household_gross_income.py b/policyengine_uk/variables/household/income/household_gross_income.py
index ce42907a7..dddcc2e83 100644
--- a/policyengine_uk/variables/household/income/household_gross_income.py
+++ b/policyengine_uk/variables/household/income/household_gross_income.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class household_gross_income(Variable):
diff --git a/policyengine_uk/variables/household/income/household_income_decile.py b/policyengine_uk/variables/household/income/household_income_decile.py
index e68d4c11e..6e1f40d74 100644
--- a/policyengine_uk/variables/household/income/household_income_decile.py
+++ b/policyengine_uk/variables/household/income/household_income_decile.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class household_income_decile(Variable):
diff --git a/policyengine_uk/variables/household/income/household_market_income.py b/policyengine_uk/variables/household/income/household_market_income.py
index ec7578c93..cfe41be1d 100644
--- a/policyengine_uk/variables/household/income/household_market_income.py
+++ b/policyengine_uk/variables/household/income/household_market_income.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class household_market_income(Variable):
diff --git a/policyengine_uk/variables/household/income/in_work.py b/policyengine_uk/variables/household/income/in_work.py
index b88e65e8b..24c3340c7 100644
--- a/policyengine_uk/variables/household/income/in_work.py
+++ b/policyengine_uk/variables/household/income/in_work.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class in_work(Variable):
diff --git a/policyengine_uk/variables/household/income/income_decile.py b/policyengine_uk/variables/household/income/income_decile.py
index 87f3f6194..767d34f86 100644
--- a/policyengine_uk/variables/household/income/income_decile.py
+++ b/policyengine_uk/variables/household/income/income_decile.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class income_decile(Variable):
diff --git a/policyengine_uk/variables/household/income/inflation_adjustment.py b/policyengine_uk/variables/household/income/inflation_adjustment.py
index 996763f91..4a84af960 100644
--- a/policyengine_uk/variables/household/income/inflation_adjustment.py
+++ b/policyengine_uk/variables/household/income/inflation_adjustment.py
@@ -1,6 +1,6 @@
-from policyengine_uk.model_api import *
 import datetime
-import numpy as np
+
+from policyengine_uk.model_api import *
 
 
 class inflation_adjustment(Variable):
diff --git a/policyengine_uk/variables/household/income/is_apprentice.py b/policyengine_uk/variables/household/income/is_apprentice.py
index abf53d985..bdc75a886 100644
--- a/policyengine_uk/variables/household/income/is_apprentice.py
+++ b/policyengine_uk/variables/household/income/is_apprentice.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class is_apprentice(Variable):
diff --git a/policyengine_uk/variables/household/income/market_income.py b/policyengine_uk/variables/household/income/market_income.py
index 9df8de09c..96fb65c49 100644
--- a/policyengine_uk/variables/household/income/market_income.py
+++ b/policyengine_uk/variables/household/income/market_income.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class market_income(Variable):
diff --git a/policyengine_uk/variables/household/income/minimum_wage.py b/policyengine_uk/variables/household/income/minimum_wage.py
index bf54d87bc..e2268f5d8 100644
--- a/policyengine_uk/variables/household/income/minimum_wage.py
+++ b/policyengine_uk/variables/household/income/minimum_wage.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class minimum_wage(Variable):
diff --git a/policyengine_uk/variables/household/income/minimum_wage_category.py b/policyengine_uk/variables/household/income/minimum_wage_category.py
index 0051e53d6..0ee2beb3b 100644
--- a/policyengine_uk/variables/household/income/minimum_wage_category.py
+++ b/policyengine_uk/variables/household/income/minimum_wage_category.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class MinimumWageCategory(Enum):
diff --git a/policyengine_uk/variables/household/income/real_household_net_income.py b/policyengine_uk/variables/household/income/real_household_net_income.py
index d762af06d..e6ff84f44 100644
--- a/policyengine_uk/variables/household/income/real_household_net_income.py
+++ b/policyengine_uk/variables/household/income/real_household_net_income.py
@@ -1,6 +1,6 @@
-from policyengine_uk.model_api import *
 import datetime
-import numpy as np
+
+from policyengine_uk.model_api import *
 
 
 class real_household_net_income(Variable):
diff --git a/policyengine_uk/variables/household/income/real_household_net_income_ahc.py b/policyengine_uk/variables/household/income/real_household_net_income_ahc.py
index 5cdd1c50e..4d7ed04a8 100644
--- a/policyengine_uk/variables/household/income/real_household_net_income_ahc.py
+++ b/policyengine_uk/variables/household/income/real_household_net_income_ahc.py
@@ -1,6 +1,6 @@
-from policyengine_uk.model_api import *
 import datetime
-import numpy as np
+
+from policyengine_uk.model_api import *
 
 
 class real_household_net_income_ahc(Variable):
diff --git a/policyengine_uk/variables/household/income/statutory_maternity_pay.py b/policyengine_uk/variables/household/income/statutory_maternity_pay.py
index abcc56920..966e076ce 100644
--- a/policyengine_uk/variables/household/income/statutory_maternity_pay.py
+++ b/policyengine_uk/variables/household/income/statutory_maternity_pay.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class statutory_maternity_pay(Variable):
diff --git a/policyengine_uk/variables/household/income/statutory_paternity_pay.py b/policyengine_uk/variables/household/income/statutory_paternity_pay.py
index 2afe4dd1f..000513521 100644
--- a/policyengine_uk/variables/household/income/statutory_paternity_pay.py
+++ b/policyengine_uk/variables/household/income/statutory_paternity_pay.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class statutory_paternity_pay(Variable):
diff --git a/policyengine_uk/variables/household/income/statutory_sick_pay.py b/policyengine_uk/variables/household/income/statutory_sick_pay.py
index 16abddf30..ef0d52d37 100644
--- a/policyengine_uk/variables/household/income/statutory_sick_pay.py
+++ b/policyengine_uk/variables/household/income/statutory_sick_pay.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class statutory_sick_pay(Variable):
diff --git a/policyengine_uk/variables/household/income/weekly_hours.py b/policyengine_uk/variables/household/income/weekly_hours.py
index e9a16ac54..db39500bf 100644
--- a/policyengine_uk/variables/household/income/weekly_hours.py
+++ b/policyengine_uk/variables/household/income/weekly_hours.py
@@ -1,6 +1,4 @@
 from policyengine_uk.model_api import *
-import datetime
-import numpy as np
 
 
 class weekly_hours(Variable):
diff --git a/policyengine_uk/variables/household/marginal_tax_rate.py b/policyengine_uk/variables/household/marginal_tax_rate.py
index 6c0345d08..2d95cfa1c 100644
--- a/policyengine_uk/variables/household/marginal_tax_rate.py
+++ b/policyengine_uk/variables/household/marginal_tax_rate.py
@@ -1,6 +1,7 @@
-from policyengine_uk.model_api import *
 from policyengine_core.variables import Variable
 
+from policyengine_uk.model_api import *
+
 
 class marginal_tax_rate(Variable):
     label = "Marginal tax rate"
diff --git a/policyengine_uk/variables/household/region.py b/policyengine_uk/variables/household/region.py
index e59932d35..7060d1036 100644
--- a/policyengine_uk/variables/household/region.py
+++ b/policyengine_uk/variables/household/region.py
@@ -1,8 +1,5 @@
 from policyengine_uk.model_api import *
-from policyengine_uk.variables.household.demographic.locations import BRMAName
 from policyengine_uk.variables.household.demographic.geography import Region
-import pandas as pd
-import numpy as np
 
 
 class region(Variable):
diff --git a/pyproject.toml b/pyproject.toml
index 3dd402e30..22be225b1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -113,3 +113,20 @@ line-length = 88
 extend-exclude = [
     "docs/book/programs/gov/dfe/care-to-learn.ipynb",
 ]
+
+[tool.ruff.lint]
+select = ["E", "F", "I"]
+ignore = [
+    "E402",  # module-import-not-at-top-of-file
+    "E501",  # line too long (handled by ruff format)
+    "E712",  # true-false-comparison (common in numpy/pandas code)
+    "E721",  # type-comparison
+    "E722",  # bare-except
+    "E741",  # ambiguous-variable-name
+    "F401",  # unused-import (many are intentional re-exports)
+    "F403",  # undefined-local-with-import-star
+    "F405",  # undefined-local-with-import-star-usage
+    "F811",  # redefined-while-unused
+    "F821",  # undefined-name (from star imports)
+    "F841",  # unused-variable
+]