Efficacy
https://fivethirtyeight.com/features/mass-shootings-are-a-bad-way-to-understand-gun-violence/?ex_cid=story-facebook
https://www.wsj.com/articles/the-gun-control-mirage-1507158925
https://www.washingtonpost.com/opinions/i-used-to-think-gun-control-was-the-answer-my-research-told-me-otherwise/2017/10/03/d33edca6-a851-11e7-92d1-58c702d2d975_story.html