|"Oh, one last thing before you go..."|
"Some have suggested that crime shows lead the public — and thus jurors — to expect amazing evidence at trial. But there’s also good news from the forensic-science department. The act of collecting DNA from convicts deters crime. Comparing recidivism rates for convicts who were released before a collection requirement went into effect to recidivism rates for convicts released after the requirement, an economist found that “the requirement to submit a DNA sample reduces the likelihood of a new conviction within five years by 4.5 percentage points (17 percent) for serious violent offenders.” And given that the incremental cost of collecting DNA from each convict is small, the incremental cost of preventing a serious crime through DNA profiling is estimated to be a tiny fraction of the incremental cost of preventing a serious crime from longer prison sentences or more police officers.
Doleac, J., “The Effects of DNA Databases on Crime,” American Economic Journal: Applied Economics (forthcoming)."