2008 was not a surprise, and it didn't come out of nowhere. Predicting the specific time the crash would happen was a bit like fortune telling but from 2006 on

2008 was not a surprise, and it didn't come out of nowhere. Predicting the specific time the crash would happen was a bit like fortune telling but from 2006 on a growing number of economists and analysts began flashing an ever increasing number of warning signs. There were even a few major warning signs before the summer of 07 when things went crazy. Economists and analysts use a wide variety of measures to predict if the economy will begin contracting, losing jobs, and potentially if that economy will start a death spiral of income loss -> spending decline -> revenue decrease -> layoffs -> income loss requiring government intervention at some stage to stop spiralling (or ya know bottom out) Depending on who you listen to, they use everything from manufacturing outputs, energy futures, consumer confidence indexes, 2/10 year bond spread, unemployment rates/claims, average wages, consumer goods sales, manufacturing supply indexes, the S&P 500 performance, inflation and money supply... Ultimately a good combination of data to predict recessions makes something like the oil temperature gauge in your car. If the temp is high, is your engine going bad? Not necessarily. But if the temp is high, is something going wrong? Probably.