sgiambra
commented
6 years ago Coverage Zillow data Zillow offers data at different geographic level: states, large metro areas, counties, cities, Zip Codes and neighborhoods. I have focused on counties and Zip Codes as a compromise between coverage and fine geographic level.
Counties
Of the 3,007 US counties (source) Zillow computes ZHVI on 1,692 counties from April 1996 through Jan 2018 (not all counties have data for every month).
Zip Codes
Of the 43,000 US Zip Codes (source) Zillow computes ZHVI on 15,327 Zip Codes from April 1996 through Jan 2018 (not all Zip Codes have data for every month).
Zip Code vs County
In most cases there is no actual difference between Zip Codes and counties. In the map below, Zip Codes for which Zillow has house prices are represented by blue shapes. White polygons represent counties covered in Zillow data while black triangles are wind turbines.
Focusing on a central area of the US
In the following example Zip Codes are shaded in dark red (blue) if log ZHVI decreased (increased) one year after the completion of the wind farm. The highlighted shape delimits the border of the county.
Zip Codes allow to capture some local heterogeneity that would be lost switching to counties.
[GOAL] Exploratory analysis of Zillow and FAA data.