In a recent study for the National Bureau of Economic Research (NBER), four researchers looked at the effect of generous unemployment benefits on the local unemployment rate. They compared the unemployment situation in adjoining counties, which happened to lie in two different states that had different laws regarding the amount and duration of unemployment benefits. (Re-read the section on "A Natural Experiment of History" in Chapter 8 of the text to understand how the NBER research is based on a "natural experiment.")The authors of the NBER study found that the unemployment rate "rises dramatically in the border counties belonging to the states that expanded unemployment benefit duration" during the Great Recession.Why might this be so?Based on Hagedorn, Karahan, et al., "Unemployment Benefits and Unemployment in the Great Recession: The Role of Macro Effects." NBER working paper 19499, October 2013.