Is This a Rental? Comparing Methods for Identifying Rental Units

Researchers regularly attempt to identify individual housing units as either owner-occupied or renter-occupied. But the data sources available to do so are rarely purpose-built for answering that question. This paper explores the most common approaches used in the literature to identify rental properties in the United States, namely by identifying properties based on characteristics listed within a tax assessment database. This study shows the possible problems associated with the current approaches to identify rental properties based on homestead exemptions or address matching. An underutilized data source — local rental registries — are introduced as a possible alternative in the cities that have them. Differences between rental registries and tax assessment databases are discussed, and the number, count, and type of rental units are compared in five cities. I identify possible sources of disagreement between data sources. This paper cautions researchers who opt to use tax assessment databases, or proprietary data sources, to identify rental units.