updated documentation for HRR/MSA levels

Author: Jingjing Tang

google_symptoms/DETAILS.md

@@ -2,11 +2,15 @@
 
 We import the normalized symptom search term popularity data from the Google 
 Research's Open COVID-19 Data project and export the county-level and state-level 
-data as-is.  
+data as-is.  We also aggregate the data to the MSA and HRR levels.
 
 ## Geographical Levels (`geo`)
 * `county`: reported using zero-padded FIPS codes.  The county level data is derived 
 from `/subregions/state/2020_US_state_daily_symptoms_dataset.csv`.
+* `msa`: reported using cbsa (consistent with all other COVIDcast sensors). The msa
+level data is derived from county level data using population weighted average.
+* `hrr`: reported using HRR number (consistent with all other COVIDcast sensors). The 
+hrr level data is derived from county level data using population weighted average.
 * `state`: reported using two-letter postal code. The state level data is derived from
 `2020_US_daily_symptoms_dataset.csv` which includes data for District of Columbia.
 

google_symptoms/README.md

@@ -2,8 +2,8 @@
 
 We import the normalized symptom search term popularity data from the Google 
 Research's Open COVID-19 Data project and export the county-level and state-level 
-data as-is.  For detailed information see the files `DETAILS.md` contained
-in this directory.
+data as-is.  We also aggregate the data to the MSA and HRR levels. For detailed 
+information see the files `DETAILS.md` contained in this directory.
 
 ## Running the Indicator