6 December 2012
Between 1991 and 2011, gross interstate migration in the United States declined by about 50 percent. Greg Kaplan
and Sam Schulhofer-Wohl
suggest that this is because of a combination of two factors: 1) a reduction in the geographic specificity of returns to different types of skills -- that is, it now matters less where your job is than what your job is; and 2) an increase in workers' information about how much they will enjoy living in alternative locations -- it's easier to use information technology and less expensive to travel, so workers can learn about other locations before they move there.
5 December 2012
The U.S. military retirement system underwent substantial changes in 1986 with the passage of the Military Retirement Reform Act, and again in 2000 when key provisions of that bill were repealed. Jeff Smith
and Jim West
study rates of officer retention under more and less generous pension benefit regimes brought about by those changes and find that reductions in benefits significantly reduce the probability of officers remaining in the military. They estimate that a 20-percent reduction in the generosity of retirement benefits has roughly the same effect on the probability of remaining on active duty as a 0.27 percentage point reduction in the unemployment rate, or a roughly 2 percent increase in the GDP growth rate.
4 December 2012
With a sample of more than 1,100 retractions of scientific papers, Pierre Azoulay
, Jeff Furman
, Josh Krieger
, and Fiona Murray
study how closely related articles that were published prior to these retractions are affected by this taint of "false science." They find that related articles experience a lasting 5-to-10 percent decline in the rate at which they are cited, although citations in for-profit publications respond less to the retractions than citations in academic publications. The decline in citations of related papers is more severe when the retracted article involves fraud or misconduct, rather than an honest mistake.
3 December 2012
Almost all 18 year-old males in Sweden who enlisted in the military between 1980 and 1994 were required to take a battery of cognitive tests in preparation for military service, but test dates were assigned randomly, so those of similar age and graduating class had accumulated slightly different days of schooling when tested. Magnus Carlsson
, Gordon Dahl
, and Dan-Olof Rooth
find that an extra ten days of school instruction raises the cognitive scores of these young men on intelligence tests.
30 November 2012
and Todd Rogers
study the short-run and long-run effects of an energy conservation initiative that involved mailing "Home Energy Reports" featuring personalized feedback, social comparisons, and energy conservation information to households monthly or every few months. This program has been running continuously since October 2008, and includes one randomly-selected group of households that stopped receiving the reports after two years. When the authors analyze over 200 million observations of daily electricity use over a six-year period, they find a pattern of "action and backsliding": consumers reduce electricity use markedly within days of receiving each of their initial reports, but their responses decay relatively quickly. However, there is a durable treatment effect that remains: for the group that continuously receives reports over a four-year period, the effects continue to grow. Even in the group whose reports were discontinued after two years, the backsliding happens more slowly, indicating that they had already formed habits of conserving.