Comparing Firearm Proxies to Legal Firearm Prevalence in Massachusetts

Overview

This study introduces legal firearm prevalence, a measure based on the population of firearm licenses in Massachusetts, in order to evaluate candidate proxies for firearm prevalence in a variety of research designs.

Status

Completed

Purpose

The most frequent proxy for firearm prevalence is the ratio of firearm suicides to total suicides. It has been validated cross-sectionally but not intertemporally, yet 36 published studies use it intertemporally. This project seeks to identify which proxies for firearm prevalence are appropriate for cross-sectional and longitudinal research.

Approach

• Define legal firearm prevalence using population of Massachusetts firearm license data.
• Use legal firearm prevalence as ground truth to compare candidate proxies against.
• Construct a balanced panel dataset of 14 Massachusetts counties from January 2010 to December 2017 to
  1. reevaluate suicide-based proxies including the proportion of firearm suicides
  2. explore the potential of firearm acquisitions to proxy for firearm prevalence.
• Compare each proxy to legal firearm prevalence using several common research designs including cross-sectional and intertemporal correlations, county/year panel regressions, and county/month panel regressions.
• Replicate several analyses to understand how crime data correlates with legal firearm prevalence using the Massachusetts data under several conditions:
  1. direct measures of legal firearm prevalence,
  2. suicide-based proxies,
  3. retail-based proxies,
  4. combination of suicide and retail-based proxies.

Significance

There is no direct measure for firearm prevalence at the national level. This project will (a) expand and update earlier validations of candidate firearm proxies, and (b) explore new candidate proxies. The results should help researchers select valid proxies and help policymakers to interpret previously published studies.

Published Research

• Proxies for Legal Firearm Prevalence

  View research View data on OSF

Investigator Bio

Jessica J. Kim is a doctoral candidate in Quantitative Marketing at the Rady School of Management, University of California, San Diego. Her research interests lie in the intersection of quantitative marketing and policy. She studies firearm purchasing behavior, empirical relationships between firearm sales and crime, and the impact of firearm policy on firearm-related behavior. She has several years of industry experience in marketing research agencies analyzing consumer behavior.