Below is a list of the steps we took to prepare the data. Those that are county specific are marked.

Restructuring

  • Select variables of interest
  • Choose Residential only properties based on Recoded Land.Use (e.g. removing hotels).
  • Remove vacant land (NA improvement value)
    • Kept mobile home even though no improvement value in James City only)
  • Remove parking lots (NA land value)
  • Remove Common Area (land use code – James City only)

Cleaning

  • For parcels with condo CoreLogic Land Use code but apartment County Land Use, change property type to match county code (Arlington only)
  • For parcel that was classified as single family but found to be multifamily though search, make into multifamily.
  • Cleaned any invalid entries found.
    • 43 bedrooms for a parcel in Arlington County for 2009, 2010
    • Misspelling of Williamsburg across all years for James City County,
  • Recode Absentee.Owner.Status into clearer factor names 
  • Single family units are listed as having 0 units. These were changed to 1.

Transformation

  • Recode Land.Use into different residential housing types.
  • Recode Number of Units in Building to match ACS categories using Land.Use Code and Number of Units
  • Create own Census tract and block group IDs based on lat and lon
  • Recode year built into ACS categories
  • Recode number of bedrooms into ACS categories
    • No way to code 0 bedrooms
  • Create constant 2013 equivalents for Improvement value, Land Value, Total Value, and Taxes
    • Place these into appropriate ACS categories