DePaul Institute for Housing Studies

Data on Housing Stock

Why is housing stock composition important?

Data on the housing stock provides context about the underlying characteristics of a neighborhood’s housing market and helps in the interpretation of patterns and trends in property sales, mortgage lending activity, foreclosure filings, and completed auctions activity. Understanding an area's housing stock can help determine the appropriate targeted strategies for stabilizing local housing markets, preserving and creating affordable rental housing, and promoting neighborhood investment.

IHS has used parcel-level information on property types from our Data Clearinghouse and aggregated data on neighborhood housing market composition to:

Aggregated information on the IHS Data Portal can be used to understand the composition of the housing market in four different geographies: Cook County subregions and municipalities and City of Chicago community areas and wards. Data on the housing stock are only available for Cook County.

Subtype available on the IHS Data Portal

  • Housing Units by Property Type. As of 2013, the share of total housing units in single family homes, condominium units, two-to-four unit buildings, and in buildings with five or more units. 

About the data

Data on housing stock composition is from the Cook County Assessor. In addition to data on property type and unit count reported here, this data set also includes information on a property's age, building construction, and assessed value for every parcel in Cook County. Central assessor offices for the collar counties do not collect similarly detailed data on property characteristics, therefore these data are only available for Cook County. 

While data on the housing stock originates from data provided by the Cook County Assessor, these data are significantly improved using a number of techniques in order to identify both property type and unit count consistently over time as is necessary for research and analysis. These data should be considered an approximation of the universe of properties and units in the County and the most current year of data should not be compared to previous years.