Archive for the ‘American Economic Journal’ Category

Driving under the (Cellular) Influence

August 13, 2013 Comments off

Driving under the (Cellular) Influence (PDF)
Source: American Economic Journal: Economic Policy (via Carnegie Mellon University)

We investigate the causal link between driver cell phone use and crash rates by exploiting a natural experiment induced by the 9pm price discontinuity that characterizes a majority of recent cellular plans. We first document a 7.2 percent jump in driver call likelihood at the 9pm threshold. Using a prior period as a comparison, we next document no corresponding change in the relative crash rate. Our estimates imply an upper bound in the crash risk odds ratio of 3.0, which rejects the 4.3 asserted by Redelmeier and Tibshirani (1997). Additional panel analyses of cell phone ownership and cellular bans confirm our results.

Explaining Charter School Effectiveness

February 7, 2013 Comments off

Explaining Charter School Effectiveness (PDF)

Source: American Economic Journal: Applied Economics (forthcoming)

Estimates using admissions lotteries suggest that urban charter schools boost student achievement, while charter schools in other settings do not. We explore student-level and school-level explanations for this difference using a large sample of lotteried applicants to charter schools in Massachusetts. In an econometric framework that isolates sources of charter effect heterogeneity, we show that urban charter schools boost achievement well beyond that of urban public school students, while non-urban charters reduce achievement from a higher baseline. Student demographics explain some of these gains since urban charters are most effective for non-whites and low-baseline achievers. At the same time, non-urban charter schools are uniformly ineffective. Our estimates also reveal important school-level heterogeneity within the urban charter sample. A non-lottery analysis suggests that urban charters with binding, well-documented admissions lotteries generate larger score gains than under-subscribed urban charter schools with poor lottery records. Using a detailed survey of school practices and characteristics, we link charter impacts to inputs such as instructional time, classroom techniques and school philosophy. The relative effectiveness of urban lottery- sample charters is accounted for by these schools’ embrace of the No Excuses approach to urban education.

The Effect of Health Insurance Coverage on the Use of Medical Services

July 9, 2012 Comments off

The Effect of Health Insurance Coverage on the Use of Medical Services (PDF)
Source: American Economic Journal (via Michael Anderson)

Substantial uncertainty exists regarding the causal effect of health insurance on the utilization of care. We exploit a sharp change in insurance coverage rates that results from young adults “aging out” of their parents’ insurance plans to estimate the effect of insurance coverage on the utilization of emergency department (ED) and inpatient services. Aging out results in an abrupt 5 to 8 percentage point reduction in the probability of having health insurance. We find that uninsured status leads to a 40 percent reduction in ED visits and a 61 percent reduction in inpatient hospital admissions.