The death penalty fails to deter crime or lower murder rates, according to an overwhelming majority of top criminologists questioned for a US university study published this week.
Just over 88 percent of 79 experts from the American Society of Criminology said they did not think the death penalty "acts as a deterrent," researchers at Chicago's Northwestern University said in a statement.
In the study based on a similar 1996 report, the criminologists were asked for responses based on "their understanding of the empirical research," and not their personal opinion of the effects of capital punishment.
The 88.2 percent negative result is only a slight rise on the 1996 study's finding of 83.6 percent.
"Our survey indicates that the vast majority of the world's top criminologists believe that the empirical research has revealed (the) deterrence hypothesis as a myth," the statement said.
Lead researchers Michael Radelet and Traci Lack said 64 percent of the general public in a 2006 survey also thought the death penalty did not reduce murder rates.
On whether abolishing the death penalty could significantly effect homicides, 87 percent replied in the negative -- little change to the 86.5 percent in the 1996 study.
And 90.5 percent said they did not think a possible sentence of life imprisonment affected murder rates.
"Over the last 20 years, the threat or use of the death penalty in the United States has been a stronger deterrent to homicide than the threat or use of long (or life) prison sentences," the statement said.
Accordingly, if the average time on death row between sentence and execution was reduced from its current 8-10 years, "there is a reason to expect that the death penalty would deter more homicides than it does today," the study's authors said.
The United States executed 37 people in 2008 and 32 in the first six months of 2009.