  Current sources of data on rental housing - such as the census or commercial
databases that focus on large apartment complexes - do not reflect recent
market activity or the full scope of the U.S. rental market. To address this
gap, we collected, cleaned, analyzed, mapped, and visualized 11 million
Craigslist rental housing listings. The data reveal fine-grained spatial and
temporal patterns within and across metropolitan housing markets in the U.S. We
find some metropolitan areas have only single-digit percentages of listings
below fair market rent. Nontraditional sources of volunteered geographic
information offer planners real-time, local-scale estimates of rent and housing
characteristics currently lacking in alternative sources, such as census data.
