Tips for spotting US recession before it becomes official

Economists look to a wide range of data -- from government, private and market sources -- to try to figure out just when things are headed downhill.

As the US nears a record-long expansion in July, the conversation is increasingly turning to when it will all end. Recessions are inherently hard to spot. The National Bureau of Economic Research’s Business Cycle Dating Committee, a panel whose determinations of when expansions begin and end are accepted as official, generally waits about a year to make a call. By the time a sustained downturn is evident in data like payrolls or gross domestic product, a contraction may have already begun.