1 / 18

More Guns, More Time: Using Add-on Gun Laws to Estimate the Deterrent Effect of Incarceration

More Guns, More Time: Using Add-on Gun Laws to Estimate the Deterrent Effect of Incarceration . David S. Abrams June 6, 2006. Add-on Gun Law Background. Enhanced prison sentences for defendants using or in possession of a firearm while committing a felony.

callie
Download Presentation

More Guns, More Time: Using Add-on Gun Laws to Estimate the Deterrent Effect of Incarceration

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. More Guns, More Time:Using Add-on Gun Laws to Estimate the Deterrent Effect of Incarceration David S. Abrams June 6, 2006

  2. Add-on Gun Law Background • Enhanced prison sentences for defendants using or in possession of a firearm while committing a felony. • Over half the states currently have such laws, mostly adopted in 1970s and 1980s. • Large range in magnitude: from 1 to 30 years; most are between 1 and 5 years • Does not include mandatory minimums

  3. Why Add-on Gun Laws? • Substantial heterogeneity in law adoption • Plausible exogeneity in adoption • Effected group already receives substantial sentence (mean 5.5 yrs, median 5 yrs for minimum robbery sentence)  Impact can be interpreted as deterrent effect

  4. Contributions • Event study methodology takes advantage of temporal variation in law introduction • Broad applicability due to length and breadth of data • Primary outcome, robbery rate, is of substantial interest • Numerous robustness checks and alternative specifications • Use of placebo laws to calculate correct standard errors

  5. Methodology • Event Study: a - reporting agency, t - time period, s - state y - outcome of interest, usually log gun robberies per capita Dist - dummy variable that is 1 in state s if period t is exactly i periods after the effective date in that state, and zero otherwise State dummies (λs), year dummies (γt), state-specific time trends (ωst), and time varying state characteristics (xst) are included.

  6. Methodology • Difference-in-Difference • Triple Difference

  7. Data • Outcomes obtained from Uniform Crime Reports reported offenses from 1965-2002 • Data is from 521 most populous agencies, representing 40% of US population, and has been hand-cleaned • Gun law effective dates from Vernick and Hepburn (2003); dates of passage collected from state codes and state legislative journals

  8. Robustness Checks • Other outcomes (total robberies, total assaults, burglaries) • Linear specification (instead of log) • Restricted comparison group (only states ever passing add-on laws) • State level data • Variation of population weighting, source of population data • Higher order time trends • Lagged dependant variables • Trend breaks

  9. Conclusions • Significant deterrent effect of add-on gun laws leads to a 5% reduction in gun robberies • This reduction in crime does not appear to come from substitution to other types • Numerous robustness checks support basic findings

More Related