The Economics of Curling

Tyler Cowen at Marginal Revolution has this to say:

Here is a Canadian study on the strongly positive economic impact of curling. The study confuses gross and net benefits, regional and national benefits, and nominal expenditures with real resource production, as such economic impact studies usually do. Commit them to the flames.

I've done similar types of economic impact studies but without committing those common errors. Typically the economic impact of anything on a local community is small.