Simon Chapman, PhD; Michael Stewart, PhD; Philip Alpers; Michael Jones, PhD
Disclaimer: Dr. Chapman was a member of the Australian Coalition for Gun Control, which advocates for firearm law reform, between 1993 and 1996. Mr. Alpers runs GunPolicy.org, a global nonpartisan clearinghouse for firearm-related data.
Disclosures: Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M18-0503.
Reproducible Research Statement:Study protocol, statistical code, and data set: See the .
Summary of statistics.
Reported P values are 2-sided. The constant model assumes that the rate of mass shootings remains constant across the full period; the changepoint model assumes that the rate differs between the before and after periods. LR = likelihood ratio.
* January 1979 to June 1996.
† July 1996 to February 2018.
‡ Based on 20 million simulations; R code (R Project for Statistical Computing) is provided in the Supplement.
Open circles indicate mass shootings. Top. Occurrences of mass shootings, 1979–1996. Bottom. Estimated rate of mass shootings per year under 2 different models. Our statistical test compared the constant rate and changepoint models, rejecting the former in favor of the latter. The vertical dashed line indicates the change at June 1996.
The In the Clinic® slide sets are owned and copyrighted by the American College of Physicians (ACP). All text, graphics, trademarks, and other intellectual property incorporated into the slide sets remain the sole and exclusive property of the ACP. The slide sets may be used only by the person who downloads or purchases them and only for the purpose of presenting them during not-for-profit educational activities. Users may incorporate the entire slide set or selected individual slides into their own teaching presentations but may not alter the content of the slides in any way or remove the ACP copyright notice. Users may make print copies for use as hand-outs for the audience the user is personally addressing but may not otherwise reproduce or distribute the slides by any means or media, including but not limited to sending them as e-mail attachments, posting them on Internet or Intranet sites, publishing them in meeting proceedings, or making them available for sale or distribution in any unauthorized form, without the express written permission of the ACP. Unauthorized use of the In the Clinic slide sets will constitute copyright infringement.
Chapman S, Stewart M, Alpers P, Jones M. Fatal Firearm Incidents Before and After Australia's 1996 National Firearms Agreement Banning Semiautomatic Rifles. Ann Intern Med. ;169:62–64. doi: 10.7326/M18-0503
Download citation file:
Published: Ann Intern Med. 2018;169(1):62-64.
Published at www.annals.org on 13 March 2018
Results provided by:
Copyright © 2019 American College of Physicians. All Rights Reserved.
Print ISSN: 0003-4819 | Online ISSN: 1539-3704
Conditions of Use