CBS Evening News allowed discredited gun researcher John Lott to attack the view that gun violence is a public health issue with the unsupported claim that murder rates have increased everywhere guns have been banned.

Lott is a well-known pro-gun advocate and frequent source of conservative misinformation about gun violence. He rose to prominence during the 1990s with the publication of his book, More Guns, Less Crime, although his conclusion that permissive gun laws reduce crime rates was later debunked by academics who found serious flaws in his research.

During an August 27 segment on CBS Evening News that discussed the shocking killing of two Virginia journalists, Lott said he did not believe gun violence was a public health issue and claimed, “Every country in the world, or place in the world, [that] has banned guns has seen an increase in murder rates, it's not just Washington, D.C. and Chicago.”

Lott's claim is unsupported by the data. It's also a red herring; in the United States, sweeping gun bans were found to be unconstitutional in the 2008 Supreme Court decision, District of Columbia v. Heller, effectively making the proposition of banning all guns irrelevant in serious policy debates over gun laws, which are focused most strongly on strengthening the background check system for firearm sales.

Lott's claim about higher murder rates where gun sales are all but banned falls apart after examining one of the cities he cites, Washington D.C.

Lott is technically correct that the D.C. murder rate in 1976 -- the year a ban on private ownership or possession of handguns in nearly all circumstances went into effect -- was 26.8 people per 100,000 residents, and was 31.4 in 2008, the last year the ban was in place. But those two data points don't tell the whole story. For example, the murder rate in the last full year in which D.C. did not have a gun ban, 1975, was 32.8  -- higher than the murder rate when the ban ended

In fact, D.C.'s murder rate during the last year of the gun ban was lower than the murder rates in each of the five years before it was implemented (31.4 vs. 32.8, 38.3, 35.9, 32.8, and 37.1).

Homicide trends in D.C. also cast doubt on Lott's suggestion of a causal connection between the District's handgun ban and number of murders. Murders in D.C. peaked in 1991 -- a crack epidemic was raging at the time -- at 80.6 per 100,000 residents. During the last 17 years D.C.'s gun ban was in effect, the rate fell by more than half, suggesting that factors other than the ban were driving the murder rate.

Data from Australia also casts doubt on Lott's premise that more restrictions on firearms equal more murders. Following a series of mass shootings that culminated with the 1996 Fort Arthur massacre of 35 people, Australia enacted extremely restrictive gun laws that placed strong limits on firearm ownership -- especially for handguns and semi-automatic rifles -- and confiscated 650,000 privately owned guns. 

After Australia implemented these laws, according The Washington Post, an academic study found that “the firearm homicide rate fell by 59 percent, and the firearm suicide rate fell by 65 percent, in the decade after the law was introduced, without a parallel increase in non-firearm homicides and suicides.”

In a more general sense, an examination of research on guns and homicide by the Harvard Injury Control Research Center found “case-control studies, ecological time-series and cross-sectional studies indicate that in homes, cities, states and regions in the US, where there are more guns, both men and women are at higher risk for homicide, particularly firearm homicide.”

Although Lott is well-known to reporters and news producers, he should not be considered a credible source for information about gun violence. In addition to his flawed research, Lott has been embroiled in a number of ethics controversies, including his admission that he used the pseudonym “Mary Rosh” to defend his works from critics and praise his own research in online discussions. He has also faced allegations that he fabricated the results of a study on defensive gun use and has been caught attempting to surreptitiously revise his data after critics discovered errors.