Studies attempting to estimate the effects of countercyclical fiscal policy have found an incredibly wide range of possibilities. While the CBO estimates a multiplier effect between 0.5 and 2.5, academic literature is even further apart. IMF economists writing about recent studies found estimates that government spending could be either significantly harmful or even more effective than the most optimistic CBO scenario. In summing up the state of macroeconomics, they found this to be an “embarrassingly wide range of estimated multipliers.”

“Usually, the CBO is very careful when they apply the range of jobs created because they don’t really know for sure,” said Douglas Holtz-Eakin, former CBO director and president of the American Action Forum. “I think it says a lot about the confidence of the profession in their ability to provide these estimates. There’s simply no consensus about the size of multiplier effects in the best of circumstances, and for those that were introduced in the midst of a large financial crisis-induced recession, it’s even more uncertain.”

The CBO’s modeling represents the wide range and uncertainty surrounding the economic community. It’s also not simply a matter of splitting the difference between the best-case and worst-case scenario being represented. The range presented is so wide precisely because economists are genuinely unsure of their methods and projections.