The Effects of DNA Databases on the Deterrence and Detection of Offenders

Abstract

Countries around the world use databases of criminal offenders' DNA profiles to match known offenders with crime scene evidence. The purpose is to ease police detection work and to increase the probability that offenders get caught if they reoffend, thereby deterring future criminal activity. We exploit a large expansion of Denmark's DNA database in 2005 to measure the effect of DNA registration on criminal behavior. Using a regression discontinuity strategy, we find that DNA registration reduces recidivism by 43%. Using rich data on the timing of subsequent charges to separate the deterrence and detection effects of DNA databases, we also find that DNA registration increases the probability that repeat offenders get caught, by 4%. We estimate an elasticity of criminal behavior with respect to the probability of detection to be -1.7. We also find suggestive evidence that DNA profiling changes non-criminal behavior: offenders added to the DNA database are more likely to get married, remain in a stable relationship, and live with their children.

Keywords: DNA, deterrence, crime, recidivism, technology