Several people have commented on the irony of Lott attacking the New York Times for a “Pattern of Deceit”, but let’s look at what he says in his article:

As an example, take the major 20,000 word series on “rampage killings” the Times published during 2000.

The paper declared that the evidence they compiled “confirmed the public perception that they appear to be increasing.” Indeed, the Times found that exactly 100 such attacks took place during the 50 years from 1949 to 1999, 51 of which occurred after the beginning of 1995. Their conclusion: “the nation needs tighter gun laws for everyone.”

Observed a Flaw

Having done a lot of work on this topic (together with Bill Landes at the University of Chicago), I immediately noticed that the Times noted virtually all the cases during the second half of the 1990s, but omitted most of the cases prior to that.

While a side bar to one of the articles briefly cautions that the series “does not include every attack,” the omissions are so extremely skewed as to produce a nine-fold increase between the 1949 to 1994 and 1995 to 1999 periods.

The Times claimed that from 1977 to 1994 there was an annual average of only 2.6 attacks where at least one person was killed in a public multiple victim attack (not including robberies or political killings). Yet, what we found was an average of 17 per year.

However if you look at what the Times actually said (payment required), you find that they did not say that there were “exactly 100 attacks”, but rather

the database does not include every attack of this type over the last 50 years.

They did not say that there was a nine-fold increase in attacks and they did not say that “from 1977 to 1994 there was an annual average of only 2.6 attacks”, but rather

Yet there is a strong impression that they have become more common. In an effort to confirm the trend, The Times analyzed F.B.I. reports of all homicides since 1976. Each year there were 15,000 to 22,000 homicides, but very few involved three or more victims.

That universe shrank even more, to just a few dozen, when The Times weeded out those involving robbery or gang violence, and those in which the primary victim was a family member.

What is left is the closest thing there is to a census of rampage killings — about one-tenth of one percent of all killings.

And it shows that in the 1990’s, they increased.

Their number remained fairly consistent from 1976 to 1989, averaging about 23 a year, only once going above 30. But between 1990 and 1997, the last year for which data was available, the number averaged over 34, dipping below 30 only once, in 1994.

”In the early 90’s, for some reason, it increased, and seems to have a different level since,” said Steven Messner, a criminologist at the State University of New York at Albany, who reviewed the numbers at the request of The Times.

The New York Times article considered two different data sets. The one they used for trends as in the quote above was based on FBI data on all homicides. The other contained 100 cases where detailed information was obtained from media reports, and did not contain all cases of rampage killings (as they made clear). The cases that were in it were skewed towards the more recent ones. Lott pretended that they used the second data set to analyse trends even though it is quite obvious from the article that they did not.