Does Death Penalty Work as Deterrent?
Protestors at an anti-death penalty rally.
Credit: Robert J. Daveant /

It’s not clear if capital punishment has any effect on homicide rates, a new study from the National Research Council concludes. 

The report evaluated studies conducted since a four-year moratorium on the death penalty was lifted in 1976, finding that studies don’t provide evidence for or against the notion that the death penalty affects homicide rates.  These studies should not be used to inform judgments about the effect of the death penalty on homicide, and should not serve as a basis for policy decisions about capital punishment, the committee said. 

The lack of evidence about the deterrent effect of capital punishment — whether it is positive, negative, or zero — should not be construed as favoring one argument over another, the report stresses.  Science simply can’t say, the report concludes.

"Fundamental flaws in the research we reviewed make it of no use in answering the question of whether the death penalty affects homicide rates," said Daniel S. Nagin, professor of public policy and statistics at Carnegie Mellon University Pittsburgh, and chair of the committee that wrote the report. "We recognize that this conclusion may be controversial to some, but no one is well-served by unsupportable claims about the effect of the death penalty, regardless of whether the claim is that the death penalty deters homicides, has no effect on homicide rates or actually increases homicides."