Handgun acquisitions in California after two Mass shootings

David M. Studdert, Yifan Zhang, Jonathan A. Rodden, Rob J. Hyndman, Garen J Wintemute

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Background: Mass shootings are common in the United States. They are the most visible form of firearm violence. Their effect on personal decisions to purchase firearms is not well-understood. Objective: To determine changes in handgun acquisition patterns after the mass shootings in Newtown, Connecticut, in 2012 and San Bernardino, California, in 2015. Design: Time-series analysis using seasonal autoregressive integrated moving-average (SARIMA) models. Setting: California. Population: Adults who acquired handguns between 2007 and 2016. Measurements: Excess handgun acquisitions (defined as the difference between actual and expected acquisitions) in the 6-week and 12-week periods after each shooting, overall and within subgroups of acquirers. Results: In the 6 weeks after the Newtown and San Bernardino shootings, there were 25 705 (95% prediction interval, 17 411 to 32 788) and 27 413 (prediction interval, 15 188 to 37 734) excess acquisitions, respectively, representing increases of 53% (95% CI, 30% to 80%) and 41% (CI, 19% to 68%) over expected volume. Large increases in acquisitions occurred among white and Hispanic persons, but not among black persons, and among persons with no record of having previously acquired a handgun. After the San Bernardino shootings, acquisition rates increased by 85% among residents of that city and adjacent neighborhoods, compared with 35% elsewhere in California. Limitations: The data relate to handguns in 1 state. The statistical analysis cannot establish causality. Conclusion: Large increases in handgun acquisitions occurred after these 2 mass shootings. The spikes were short-lived and accounted for less than 10% of annual handgun acquisitions statewide. Further research should examine whether repeated shocks of this kind lead to substantial increases in the prevalence of firearm ownership.

Original languageEnglish (US)
Pages (from-to)698-706
Number of pages9
JournalAnnals of Internal Medicine
Volume166
Issue number10
DOIs
StatePublished - May 16 2017

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Firearms
Ownership
Hispanic Americans
Violence
Causality
Shock
Research
Population

ASJC Scopus subject areas

  • Internal Medicine

Cite this

Handgun acquisitions in California after two Mass shootings. / Studdert, David M.; Zhang, Yifan; Rodden, Jonathan A.; Hyndman, Rob J.; Wintemute, Garen J.

In: Annals of Internal Medicine, Vol. 166, No. 10, 16.05.2017, p. 698-706.

Research output: Contribution to journalArticle

Studdert, DM, Zhang, Y, Rodden, JA, Hyndman, RJ & Wintemute, GJ 2017, 'Handgun acquisitions in California after two Mass shootings', Annals of Internal Medicine, vol. 166, no. 10, pp. 698-706. https://doi.org/10.7326/M16-1574
Studdert, David M. ; Zhang, Yifan ; Rodden, Jonathan A. ; Hyndman, Rob J. ; Wintemute, Garen J. / Handgun acquisitions in California after two Mass shootings. In: Annals of Internal Medicine. 2017 ; Vol. 166, No. 10. pp. 698-706.
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abstract = "Background: Mass shootings are common in the United States. They are the most visible form of firearm violence. Their effect on personal decisions to purchase firearms is not well-understood. Objective: To determine changes in handgun acquisition patterns after the mass shootings in Newtown, Connecticut, in 2012 and San Bernardino, California, in 2015. Design: Time-series analysis using seasonal autoregressive integrated moving-average (SARIMA) models. Setting: California. Population: Adults who acquired handguns between 2007 and 2016. Measurements: Excess handgun acquisitions (defined as the difference between actual and expected acquisitions) in the 6-week and 12-week periods after each shooting, overall and within subgroups of acquirers. Results: In the 6 weeks after the Newtown and San Bernardino shootings, there were 25 705 (95{\%} prediction interval, 17 411 to 32 788) and 27 413 (prediction interval, 15 188 to 37 734) excess acquisitions, respectively, representing increases of 53{\%} (95{\%} CI, 30{\%} to 80{\%}) and 41{\%} (CI, 19{\%} to 68{\%}) over expected volume. Large increases in acquisitions occurred among white and Hispanic persons, but not among black persons, and among persons with no record of having previously acquired a handgun. After the San Bernardino shootings, acquisition rates increased by 85{\%} among residents of that city and adjacent neighborhoods, compared with 35{\%} elsewhere in California. Limitations: The data relate to handguns in 1 state. The statistical analysis cannot establish causality. Conclusion: Large increases in handgun acquisitions occurred after these 2 mass shootings. The spikes were short-lived and accounted for less than 10{\%} of annual handgun acquisitions statewide. Further research should examine whether repeated shocks of this kind lead to substantial increases in the prevalence of firearm ownership.",
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