[jordanb]

"Two consecutive quarters of negative GDP growth" is just a "rule ... economists made up" too. And a totally arbitrary (albeit seductively simple) one at that. The NBER look at when the economy actually starts slowing down, not when some arbitrary amount of time has passed after the sign on national GDP growth flipped over. It is more complicated, yes, but also more sophisticated and rigorous than the old rule of thumb.

When it comes to indicators, the fact is that the definition of 'recession' is pretty irrelevant. Your rule of thumb is backward-looking and thus pretty much useless for figuring out how the economy is going to move anyway. You can't know the economy is in trouble until it's already been there for two quarters, eh?

Likewise with unemployment, if you ignore the other indicators you won't know something is going wrong until you're already deep into it (and it starts getting reflected in unemployment data). Whereas if you pay attention to leading indicators like productivity, you'll be able to better predict what unemployment is going to do.