The advent of smart‐phone based, ride‐sharing applications has revolutionized the vehicle for hire market. Advocates point to the ease of use, lower prices, and shorter wait times compared to hailing a taxi or prearranging limousine service. Others argue that proper government oversight is necessary to protect ride‐share passengers from driver error or vehicle parts failures and violence from unlicensed strangers. Using U.S. county‐level data from 2007 through 2015, we investigate whether the introduction of the ride‐sharing service Uber is associated with changes in fatal vehicle crashes and crime. We find that Uber's entry lowers the rate of DUIs and fatal accidents. For some specifications, we also find declines in arrests for assault and disorderly conduct. Conversely, we observe an increase in vehicle thefts.
Today's children experience a decreased amount of time at recess and fewer physical education (PE) classes throughout the school day. Breaks for physical activity limit class time for academics, potentially reducing learning. However, breaks may improve alertness and achievement. Using the Early Childhood Longitudinal Survey Kindergarten Class of 1998-1999, we evaluate how recess and PE in elementary school influence children's learning. We find no statistically significant or economically significant impacts of weekly recess or PE time on student learning for kindergarteners through fifth graders. For example, in kindergarten, adding an hour a week of recess reduces the average test score gain in reading by a statistically insignificant 0.01 standard deviations. An additional 49 minutes per week of PE in kindergarten improves reading test score gains by a statistically insignificant 0.05 standard deviations. We find no statistical difference in the male and female students' response to recess and PE. Evidence suggests that recess and PE do not harm student outcomes.
This project requested and received IRB approval from Harvard University. Monitoring the Future requests that authors allow them to review papers prior to publication. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. At least one co-author has disclosed a financial relationship of potential relevance for this research. Further information is available online at http://www.nber.org/papers/w23779.ack NBER working papers are circulated for discussion and comment purposes. They have not been peer-reviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.
This paper uses state-level data on cirrhosis death rates to examine the impact of state prohibitions, pre-1920 federal anti-alcohol policies, and constitutional prohibition on cirrhosis. State prohibitions had a minimal impact on cirrhosis, especially during the pre-1920 period. Pre-1920 federal antialcohol policies may have contributed to the decline in cirrhosis that occurred before 1920, although other factors were likely substantial influences as well. Constitutional prohibition reduced cirrhosis by about 10-20 percent.
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