"Out of 440 active shooter incidents from 2014 to 2022, an armed citizen stopped 157. We also found that the FBI had misidentified five cases, usually because the person who stopped the attack was incorrectly identified as a security guard.

"The FBI continues to report that armed citizens stopped only 14 of the 302 active shooter incidents that it identified for the period 2014-2022. The correct rate is almost eight times higher. And if we limit the discussion to places where permit holders were allowed to carry, the rate is eleven times higher."

-- John Lott
https://crimeresearch.org/2023/08/massive-errors-in-fbis-active-shooting-reports-from-2014-2022-regarding-cases-where-civilians-stop-attacks-instead-of-4-6-the-correct-number-is-at-least-35-7-in-2022-it-is-at-least-41-3/