The monthly Census measure that counts new residential construction projects begun is housing starts.
In U.S. housing statistics, a construction “start” occurs when excavation begins for a building’s footings or foundation. For a multifamily building, all housing units are counted as started when that excavation begins, even though individual apartments may be completed at different times.
Housing starts are one phase in the Census Bureau’s New Residential Construction program, alongside building permits, units authorized but not started, units under construction, and completions. The series covers new privately owned housing and excludes categories such as most mobile homes, group quarters, and units created inside existing structures.
A common mix-up is treating building permits as starts. A permit signals authorization and may never lead to construction; a start indicates that physical work has actually begun. Housing starts are therefore watched as a timelier gauge of builders’ activity, although weather, permitting delays, financing costs, and revisions can affect the monthly figures.