​I am an Associate Professor in the Department of Criminology at the University of Pennsylvania.  I am also a Senior Fellow at the Niskanen Center, a research associate at the National Bureau of Economic Research and a research affiliate at the University of Chicago Crime Lab. 

My current research focuses on the costs and benefits of policing, the preferences of police officers, place-based crime prevention and the determinants of crime victimization.  I am also interested in research that advances social science research methods and have written on topics such as measurement errors in observational data, measuring spatial crime concentration and the empirical implications of administrative data linking.  In the past, I've written on immigration enforcement, capital punishment and several other topics.
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A copy of my curriculum vitae can be viewed here.​  
My Google Scholar profile is here. ​