Every Monday, the National Bureau of Economic Research, a nonprofit organization made up of some of North America’s most respected economists, releases its latest batch of working papers. The papers aren’t peer-reviewed, so their conclusions are preliminary (and occasionally flat-out wrong). But they offer an early peek into some of the research that will shape economic thinking in the years ahead. Here are a few of this week’s most interesting papers:
Authors: Lin Cui, Randall Walsh
What they found: In Pittsburgh, foreclosures alone did not influence crime, but when a foreclosed home was abandoned, violent crime rates increased in the surrounding neighborhood.
Why it matters: The conventional wisdom is that foreclosures lead to crime, but this paper shows that the relationship is more complex. When a house goes into foreclosure, it doesn’t necessarily result in higher crime rates in the surrounding area, according to the research. The real trigger is when the residents vacate the foreclosed home. Interestingly, the researchers found that only violent crime in Pittsburgh increased; property crime was unaffected.
Key quote: “Using detailed data on addresses and dates of foreclosures and crime, we estimate that, on average, violent crimes within 250 feet of foreclosed homes increases by roughly 19% once the foreclosed home becomes vacant, compared to crimes in areas between 250 and 353 feet away. Foreclosure alone is found to have no effect on violent crime.”
Data they used: Crime data from the Pittsburgh police department; foreclosure filings data from City of Pittsburgh court records; data from Allegheny County on housing transactions and characteristics.
Authors: Nils Wernerfelt, David Slusky, Richard Zeckhauser
What they found: A pregnant woman’s low level of vitamin D during the second trimester increases the odds of her child later becoming asthmatic.
Why it matters: Asthma afflicts over 300 million people worldwide, and 1-in-12 Americans. Yet the causes of asthma remain poorly understood. These researchers believe they’ve found one significant cause: lack of sunlight, which is a major source of vitamin D. Controlling for time of year and location, they found that children were admitted to the emergency room for asthma attacks 20 percent less often when their mother had twice as much sunlight exposure during her second trimester.
Key quote: “Our results suggest low levels of maternal vitamin D during pregnancy may be more harmful than previously thought. As mentioned earlier, vitamin D deficiency and insufficiency are extremely widespread, with multiple studies of pregnant women documenting overall rates in excess of 80% (Bodnar et al., 2007; Holmes et al., 2009; Johnson et al., 2011). Hence, our results suggest that if we could raise vitamin D levels in these women, the savings in terms of both future quality of life and healthcare costs could be substantial.”
Data they used: U.S. county-level data on more than 2.1 million births.
Authors: Ginger Zhe Jin, Jungmin Lee
What they found: First-time restaurant hygiene inspectors report about 15 percent more violations than repeat inspectors.
Why it matters: Keeping restaurants clean is a duty of public health regulators, but it comes with thorny game theory problems. The thinking has been if you inspect restaurants on multiple occasions, and randomly, the restaurants won’t be able to game the system. But it matters who the inspectors are. If the same person inspects the restaurant on multiple occasions, then they report fewer violations — specifically between 1 and 2 percent fewer violations, as this paper reports. But if the inspections are conducted by different people, the number of violations increased about 13 and 18 percent.
Key quote: “We use restaurant hygiene inspections as an example to show that inspector assignment and repetition can have significant impact on inspection outcomes. In particular, we find that new inspectors report 12.7-17.5% more violations than the second visit of a repeat inspector, and this effect is more pronounced if the previous inspector has had a longer relationship with the restaurant. The difference between new and repeat inspectors is attributed to two factors: (1) new inspectors tend to have fresher eyes in their first visit of a restaurant; and (2) inspectors differ greatly in stringency and taste, such inspector heterogeneity motivates restaurants to adjust their compliance effort according to the criteria of their previous inspectors. Both factors are found to be important in our data.”
Data they used: Restaurant hygiene inspections in Florida from July 2003 and March 2010.