Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Simultaneity complicates the estimation of the causal effect of police on crime. We overcome this obstacle by focusing on a mass layoff of Oregon State Police in February of 2003. Due solely to budget cuts, 35 percent of the roadway troopers were laid off, which dramatically reduced citations. The subsequent decrease in enforcement is associated with a significant increase in injuries and fatalities. The effects are similar using control groups chosen either geographically or through data-driven methods. Our estimates suggest that a highway fatality can be prevented with $309,000 of expenditures on state police.