The number of new residential housing units on which construction begins in a given month is called housing starts.
The measure counts construction that has actually begun, not merely a project that has received permission. In U.S. statistics, the unit of count is the housing unit: each apartment in a multi-unit building counts separately. Thus, one 30-unit apartment building contributes 30 starts rather than one.
Housing starts are watched as an economic indicator because residential construction affects builders, materials suppliers, manufacturers, lenders, and local employment. A sustained rise can signal stronger confidence or demand, while a decline may point to higher borrowing costs, weaker sales expectations, land constraints, or tighter financing.
Building permits are an earlier authorization measure, and housing completions record projects finished. New home sales track transactions, not construction activity. These indicators can diverge: permits may be issued without immediate construction, and a project can start months before the completed homes are sold. Monthly starts are also volatile, especially because apartment construction can arrive in large batches.