With last week's stock market sputter and re­­newed warnings of a recession, policymakers and presidential candidates are hawking countless plans to jump-start the economy. These proposals are often complex, sometimes controversial, and almost always conjectural.

If only there were a way to take them for a test drive.

Robert Bloomfield is tinkering with such a plan. As an accounting professor at Cornell University, in Ithaca, N.Y., he researches virtual worlds