diff --git a/.github/workflows/analysis.yml b/.github/workflows/analysis.yml
new file mode 100644
index 00000000..f33bcd1a
--- /dev/null
+++ b/.github/workflows/analysis.yml
@@ -0,0 +1,27 @@
+name: Analysis
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  test:
+    strategy:
+      fail-fast: false
+      max-parallel: 20
+    runs-on: ubuntu-latest
+
+    env:
+      CI: true
+      RAILS_ENV: test
+
+    name: leftovers
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ruby/setup-ruby@v1
+        with:
+          bundler-cache: true
+
+      - run: bin/leftovers
diff --git a/.leftovers.yml b/.leftovers.yml
new file mode 100644
index 00000000..81ba168f
--- /dev/null
+++ b/.leftovers.yml
@@ -0,0 +1,45 @@
+# for instructions on how to address these
+# see https://github.com/robotdana/leftovers/tree/v0.12.2/README.md#how-to-resolve
+
+exclude_paths:
+  - 'vendor/**/*'
+
+keep:
+  # Policies are used by Pundit to determine what a user can and cannot do.
+  # Ideally we'd keep track of which policies are actually used, but we
+  # haven't figured out a way to do that yet.
+  - path: 'app/policies/*_policy.rb'
+    privacy: public
+    type: Method
+    names:
+      - create?
+      - destroy?
+      - edit?
+      - index?
+      - permitted_attributes
+      - resolve
+      - show?
+      - update?
+  - path: 'app/policies/*_policy.rb'
+    type: Constant
+    name:
+      - has_suffix: Policy
+
+  # Mailer previews are used to display emails in the browser.
+  # They're not used in production, but they're useful for development.
+  - path: 'spec/mailers/previews/*_preview.rb'
+    privacy: public
+    type: Constant
+    name:
+      - has_suffix: Preview
+
+dynamic:
+  # Nested associations are usually assigned in our controllers,
+  # but the process is often too indirect for leftovers to spot.
+  - path: 'app/models/*.rb'
+    name: accepts_nested_attributes_for
+    calls:
+      argument: '*'
+      transforms:
+        - add_suffix: '_attributes'
+        - add_suffix: '_attributes='
diff --git a/Gemfile b/Gemfile
index d80ceb7d..0acf3d62 100644
--- a/Gemfile
+++ b/Gemfile
@@ -50,6 +50,7 @@ group :development, :test do
   gem "factory_bot_rails", "~> 6.0"
   gem "faker"
   gem "i18n-tasks", "~> 0.9.6"
+  gem "leftovers", require: false
   gem "rspec-rails"
 end
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 37b814c5..c5fdcb2b 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -141,6 +141,7 @@ GEM
       faraday-net_http (>= 2.0, < 3.2)
     faraday-net_http (3.1.0)
       net-http
+    fast_ignore (0.17.4)
     ffi (1.16.3)
     fog-aws (3.21.0)
       fog-core (~> 2.1)
@@ -202,6 +203,10 @@ GEM
     language_server-protocol (3.17.0.3)
     launchy (2.5.2)
       addressable (~> 2.8)
+    leftovers (0.12.2)
+      fast_ignore (>= 0.17.0)
+      parallel
+      parser
     letter_opener (1.8.1)
       launchy (>= 2.2, < 3)
     letter_opener_web (2.0.0)
@@ -479,6 +484,7 @@ DEPENDENCIES
   jsonapi-serializer
   kaminari
   launchy
+  leftovers
   letter_opener_web
   listen
   net-imap
diff --git a/app/channels/application_cable/channel.rb b/app/channels/application_cable/channel.rb
index 9aec2305..71e17714 100644
--- a/app/channels/application_cable/channel.rb
+++ b/app/channels/application_cable/channel.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-module ApplicationCable
+module ApplicationCable # leftovers:keep
   class Channel < ActionCable::Channel::Base
   end
 end
diff --git a/app/channels/application_cable/connection.rb b/app/channels/application_cable/connection.rb
index 8d6c2a1b..a756c637 100644
--- a/app/channels/application_cable/connection.rb
+++ b/app/channels/application_cable/connection.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-module ApplicationCable
+module ApplicationCable # leftovers:keep
   class Connection < ActionCable::Connection::Base
   end
 end
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index ae62d647..74224d4b 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -19,7 +19,7 @@ class ApplicationController < ActionController::Base
   before_action :set_paper_trail_whodunnit
 
   # Allow pundit to authorize a non-logged in user
-  def pundit_user
+  def pundit_user # leftovers:keep
     current_user || User.new
   end
 
diff --git a/app/controllers/impact_omniauth_callbacks_controller.rb b/app/controllers/impact_omniauth_callbacks_controller.rb
index b91e62f5..277a720b 100644
--- a/app/controllers/impact_omniauth_callbacks_controller.rb
+++ b/app/controllers/impact_omniauth_callbacks_controller.rb
@@ -1,11 +1,11 @@
 # frozen_string_literal: true
 
-class ImpactOmniauthCallbacksController < DeviseTokenAuth::OmniauthCallbacksController
+class ImpactOmniauthCallbacksController < DeviseTokenAuth::OmniauthCallbacksController # leftovers:keep
   def auth_hash
     @_auth_hash ||= request.env["omniauth.auth"] ||= session.delete("dta.omniauth.auth")
   end
 
-  def get_resource_from_auth_hash
+  def get_resource_from_auth_hash # leftovers:keep
     super
 
     if @resource
diff --git a/app/jobs/send_category_due_emails_job.rb b/app/jobs/send_category_due_emails_job.rb
index c01b1e07..7c3544e0 100644
--- a/app/jobs/send_category_due_emails_job.rb
+++ b/app/jobs/send_category_due_emails_job.rb
@@ -1,4 +1,6 @@
-class SendCategoryDueEmailsJob < ApplicationJob
+# This is currently uncalled because it lacks an entry in Scheduler.rb
+# Maybe we can delete it?
+class SendCategoryDueEmailsJob < ApplicationJob # leftovers:keep
   queue_as :default
 
   def perform
diff --git a/app/models/category.rb b/app/models/category.rb
index b6739cee..c55609fc 100644
--- a/app/models/category.rb
+++ b/app/models/category.rb
@@ -8,7 +8,7 @@ class Category < VersionedRecord
   has_many :measure_categories, inverse_of: :category, dependent: :destroy
   has_many :sdgtarget_categories, inverse_of: :category, dependent: :destroy
   has_many :recommendations, through: :recommendation_categories
-  has_many :users, through: :user_categories
+  has_many :users, through: :user_categories # leftovers:keep
   has_many :measures, through: :measure_categories
   has_many :indicators, through: :recommendations
   has_many :indicators_via_measures, through: :recommendations
diff --git a/app/models/framework.rb b/app/models/framework.rb
index 69a2bdcd..1d234ab0 100644
--- a/app/models/framework.rb
+++ b/app/models/framework.rb
@@ -3,7 +3,7 @@ class Framework < ApplicationRecord
   has_many :frameworks, through: :framework_frameworks, source: :other_framework
 
   has_many :framework_taxonomies, inverse_of: :framework, dependent: :destroy
-  has_many :taxonomies, through: :framework_taxonomies
+  has_many :taxonomies, through: :framework_taxonomies # leftovers:keep
 
   has_many :recommendations
 
diff --git a/app/models/role.rb b/app/models/role.rb
index 75b5bf00..5b3b8267 100644
--- a/app/models/role.rb
+++ b/app/models/role.rb
@@ -1,4 +1,4 @@
 class Role < ApplicationRecord
   has_many :user_roles
-  has_many :users, through: :user_roles
+  has_many :users, through: :user_roles # leftovers:keep
 end
diff --git a/app/models/taxonomy.rb b/app/models/taxonomy.rb
index 4c7634dd..7627442c 100644
--- a/app/models/taxonomy.rb
+++ b/app/models/taxonomy.rb
@@ -1,7 +1,7 @@
 class Taxonomy < VersionedRecord
   has_many :categories
   belongs_to :taxonomy, class_name: "Taxonomy", foreign_key: :parent_id, optional: true
-  has_many :taxonomies, class_name: "Taxonomy", foreign_key: :parent_id
+  has_many :taxonomies, class_name: "Taxonomy", foreign_key: :parent_id # leftovers:keep
 
   has_many :framework_taxonomies, inverse_of: :taxonomy, dependent: :destroy
   has_many :frameworks, through: :framework_taxonomies
@@ -24,10 +24,6 @@ def sub_relation
     end
   end
 
-  def self.current_reporting_cycle
-    find(current_reporting_cycle_id)
-  end
-
   def self.current_reporting_cycle_id
     Rails.application.config.x.reporting_cycle_taxonomy_id
   end
diff --git a/app/models/user.rb b/app/models/user.rb
index 5ea92040..6e8adce7 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -11,8 +11,8 @@ class User < VersionedRecord
 
   has_many :user_roles, dependent: :destroy
   has_many :roles, through: :user_roles
-  has_many :managed_categories, foreign_key: :manager_id, class_name: "Category"
-  has_many :managed_indicators, foreign_key: :manager_id, class_name: "Indicator"
+  has_many :managed_categories, foreign_key: :manager_id, class_name: "Category" # leftovers:keep
+  has_many :managed_indicators, foreign_key: :manager_id, class_name: "Indicator" # leftovers:keep
   has_many :user_categories
   has_many :categories, through: :user_categories
   has_many :bookmarks
diff --git a/app/serializers/fast_versioned_serializer.rb b/app/serializers/fast_versioned_serializer.rb
index 2c328dcc..fa7aae0f 100644
--- a/app/serializers/fast_versioned_serializer.rb
+++ b/app/serializers/fast_versioned_serializer.rb
@@ -4,11 +4,12 @@ module FastVersionedSerializer
   def self.included(base)
     base.include FastApplicationSerializer
 
-    base.attribute :created_by_id
-    base.attribute :updated_by_id
+    base.attribute :created_by_id # leftovers:keep
+    base.attribute :updated_by_id # leftovers:keep
   end
 
-  def current_user_has_permission?
+  # This appears to be uncalled but I'm not 100% sure. Maybe we can delete it?
+  def current_user_has_permission? # leftovers:keep
     current_user&.role?("admin") || current_user&.role?("manager")
   end
 end
diff --git a/bin/leftovers b/bin/leftovers
new file mode 100755
index 00000000..e02990d7
--- /dev/null
+++ b/bin/leftovers
@@ -0,0 +1,16 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+# The application 'leftovers' is installed as part of a gem, and
+# this file is here to facilitate running it.
+
+require "pathname"
+ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../Gemfile",
+  Pathname.new(__FILE__).realpath)
+
+bundle_binstub = File.expand_path("../bundle", __FILE__)
+
+require "rubygems"
+require "bundler/setup"
+
+load Gem.bin_path("leftovers", "leftovers")
diff --git a/config/application.rb b/config/application.rb
index 49c8b1a5..a9b0f79c 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -8,7 +8,7 @@
 # you've limited to :test, :development, or :production.
 Bundler.require(*Rails.groups)
 
-module HumanRightsNationalReporting
+module HumanRightsNationalReporting # leftovers:keep
   class Application < Rails::Application
     # Settings in config/environments/* take precedence over those specified here.
     # Application configuration should go into files in config/initializers
diff --git a/db/seeds.rb b/db/seeds.rb
index f808ebae..55d6836d 100644
--- a/db/seeds.rb
+++ b/db/seeds.rb
@@ -1349,7 +1349,7 @@ def base_seeds!
     )
   end
 
-  def development_seeds!
+  def development_seeds! # leftovers:keep
     nil unless User.count.zero?
   end
 
diff --git a/scheduler.rb b/scheduler.rb
index 627ae6b6..49f68191 100644
--- a/scheduler.rb
+++ b/scheduler.rb
@@ -2,7 +2,7 @@
 require File.expand_path("../config/environment", __FILE__)
 require "clockwork"
 
-module Clockwork
+module Clockwork # leftovers:keep
   every(1.day, "Send Due Emails", at: "10:30", tz: Rails.application.config.time_zone) do
     SendDueEmailsJob.perform_now
   end
@@ -11,6 +11,8 @@ module Clockwork
     SendOverdueEmailsJob.perform_now
   end
 
+  # Should this also have a call to send Category Due Emails?
+
   every(1.day, "Send Category Overdue Emails", at: "9:15", tz: Rails.application.config.time_zone) do
     SendCategoryOverdueEmailsJob.perform_now
   end
diff --git a/spec/support/controller_macros.rb b/spec/support/controller_macros.rb
index 34d7525f..2f0e5d9c 100644
--- a/spec/support/controller_macros.rb
+++ b/spec/support/controller_macros.rb
@@ -11,9 +11,4 @@ def sign_in(user = double("user"))
     end
     user
   end
-
-  def sign_in_admin
-    user = sign_in
-    allow(user).to receive(:role?).with("admin").and_return(true)
-  end
 end
diff --git a/spec/support/feature_spec_helpers.rb b/spec/support/feature_spec_helpers.rb
deleted file mode 100644
index b7cddea6..00000000
--- a/spec/support/feature_spec_helpers.rb
+++ /dev/null
@@ -1,5 +0,0 @@
-module FeatureSpecHelpers
-  def flash?(content)
-    page.has_css?(".callout", text: content)
-  end
-end