See here for an economist's take on that: http://www.marginalrevolution.com/marginalrevolution/2010/07/zero-marginal-product-workers.html http://www.marginalrev

See here for an economist's take on that: http://www.marginalrevolution.com/marginalrevolution/2010/07/zero-marginal-product-workers.html http://www.marginalrevolution.com/marginalrevolution/2010/07... He notes that there's been "[a] recovery in output, but not in employment. That means a smaller number of laborers are working, but we are producing as much as before. As a simple first cut, how should we measure the marginal product of those now laid-off workers? I would start with the number zero. " Also here (linked in the above article): http://econlog.econlib.org/archives/2010/07/the_zmp_hypothe.html http://econlog.econlib.org/archives/2010/07/the_zmp_hypothe.... Kling's pet theory is "recalculation," in that recessions are frequently the result of lots of people being employed doing the wrong thing (in this instance, building and selling houses), and it takes a while for those workers to be "reassigned" by the market to productive jobs. Money quote here: " Let us talk about the marginal product of worker i in occupation j. In most cases, this is indeed zero. My marginal product would be zero in fishing, medicine, and many other fields. In a complex economy, if you were to randomly assign workers to jobs, ZMP would be the norm, not the exception. The more complex the economy, the more carefully workers must be assigned in order to avoid ZMP."