Q: How many economists does it take to screw in a light bulb?
1. Just one, but it really gets screwed.
2. One to prepare the proposal, an econometrician to run the model, one each MS and PhD students to write the theses and dissertations, two more to prepare the journal article (senior authorship not assigned), four to review it, and at least as many to refine the model and replicate the results.