Death Penalty as Deterrent
Does the death penalty act as a deterrent? That's a hotly debated question, but a number of studies suggest that the answer is "yes":
Among the conclusions:
Each execution deters an average of 18 murders, according to a 2003 nationwide study by professors at Emory University. (Other studies have estimated the deterred murders per execution at three, five and 14).
Of course, opponents of the death penalty are bound and determined to discredit the findings, but what's so surprising about this? It's a simple fact that people modify their behavior based on incentives, both positive and negative. Unless you believe that all (or even most) murderers are completely unhinged (in which case they would not be subject to the death penalty anyway), they would respond to incentives, and the death penalty represents a pretty strong negative incentive towards murder. Another conclusion:
Speeding up executions would strengthen the deterrent effect. For every 2.75 years cut from time spent on death row, one murder would be prevented, according to a 2004 study by an Emory University professor.
And this makes perfect sense, when viewed from the perspective of incentives. The greater the likelihood of being caught and quickly brought to justice, the greater the disincentive towards murder. It's the same sort of calculation that results in drops in violent crime in states that enact concealed carry laws. When the potential cost of trying to carjack or mug someone may be your life, you're going to think twice about whether it's worth the risk.
Source: Death Penalty Deters Murders, Studies Say, Hotly Debated Academic Analyses Claim Up To 18 Lives Saved Per Execution - CBS News via The Corner