A review of the literature studying the effect of right-to-carry laws shows that the weight of evidence indicates that such laws reduced violent crime.
However, more recent studies, using more recent data, tend to find that these laws cause increases in various kinds of violent crime, raising the possibility that circumstances have changed since 2000, causing these laws to become detrimental.
We suggest that these recent studies, which do not use all the available data, are seriously compromised because they compare states that only recently have adopted right-to-carry laws with states that have had these laws for many years, instead of comparing against states with more restrictive laws.
Early adopting states experienced relatively large reductions in crime corresponding to large increases in the number of right-to-carry permits. Late adopting states passed rules making it difficult to obtain permits and exercise the right to carry concealed weapons. Ignoring the fact that these late adopting states with stricter rules on obtaining permits issue relatively few permits can produce perverse results where coefficients imply an increase in crime even though the opposite is true.
We demonstrate this effect with a simple statistical test.SSRN-id3850436