Study Looks at Impacts of State DNA Database Laws

Research has shown that DNA databases are effective tools for reducing crime at a state level — but how do the DNA database policies in one state affect crime rates in other states? A study by Jennifer Doleac of the University of Virginia, funded by the National Institute of Justice, sought to examine those effects.

"Each state will weigh its own costs and benefits when making policy decisions, without regard for their effects on other states," writes Doleac. "But state DNA databases do not exist in a vacuum: they could have effects on criminal behavior elsewhere. The federal government can improve the national efficiency of state-level policies by inducing states to consider the costs and benefits to their neighbors — i.e., to internalize the externalities."

The report aimed to answer the following questions:

1. Does the addition of an offender or arrestee profile to CODIS by one state help or hurt other states, in terms of crime outcomes?

2. Do these effects vary with distance from the state that added the profile?

3. Do these effects vary with the type of offender who is added?

4. Do these effects depend on whether a state allows partial-match searches of CODIS?

From the abstract:

The study concludes that the cross-state effects of DNA database policies (i.e., the types of offenses for which DNA profiles are required and included in the state’s database) are consistent with the hypothesis that offenders are mobile and respond rationally to states’ crime-reduction strategies. It is apparent that a DNA expansion in one state motivates probable offenders in that state to move to states where DNA databases are not as comprehensive.

This suggests that expanding the offenses with DNA coverage in one state will have the effect of offenders moving to other states to commit crime, thus increasing crime in the destination state. Given these findings, this study argues that the federal government should stop subsidizing state-level expansions of DNA databases, since an imbalance in states’ DNA databases encourages mobile offenders to take their crimes to other states where a DNA identification is less likely. Thus, there is no net effect on crime nationwide. A better approach is for the federal government to standardize DNA database policies nationwide, which would eliminate incentives for offenders to move.

You can read the full report here.

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