Just when America is coming to its senses about the barbarity and futility of capital punishment, Amitai Etzioni writes, some economists with misleading, half-baked stats muddy the facts.

The economists have “a model that, they say, shows that the death penalty deters crimes and hence saves lives,” says Etzioni. “Because most people do not read the math involved and have a hard time following the intricacies of these models, these kinds of ‘findings’ are often taken seriously. . . .

“Actually the data on which this model is based are extremely thin. First, there are simply not enough executions for most statistical methods to work properly; in 2003, while there were more than 16,000 homicides nationwide, there were only 65 executions. Adding to this statistical shortfall, too many other factors change over the same period as the number of executions changes to permit a sound conclusion. These include the overall crime rates, policing methods, gun laws, levels of economic growth and of upward mobility, drug rehabilitation and education policy, among others. Things are complicated even further when one recognizes that these factors differ not only over time but also among various states that execute more people than others. The economists gloss over such challenges by using dummy variables, artificial weights, and other slights of hand.

“But all that the economists ultimately demonstrate is some (deeply questionable) correlation between capital punishment and murder. That is, they show that as the number of executions increased, homicide rates decreased. It doesn’t take a doctorate in economics to know that correlation does not prove causality.”

He has other objections too. Read more here.