YES, it DOES...Let's look at California, they have done extensive studies...
Using conservative rough projections, the Commission estimates the annual costs of
the present (death penalty) system to be $137 million per year.
The cost of the present system with reforms recommended by the Commission to ensure a fair process would be $232.7 million per year.
The cost of a system in which the number of death-eligible crimes was significantly narrowed would be $130 million per year.
The cost of a system which imposes a maximum penalty of
lifetime incarceration instead of the death penalty would be $11.5 million per year.
Commission on the Fair Administration of Justice, June 30, 2008).
Let me ask you one question...HOW would you justify just ONE innocent person being put to death?
There is no way to tell how many of the over 1,000 people executed since 1976 may also have been innocent. Courts do not generally entertain claims of innocence when the defendant is dead. Defense attorneys move on to other cases where clients' lives can still be saved. Some cases with strong evidence of innocence include:
Carlos DeLuna Texas Conviction: 1983, Executed: 1989
Ruben Cantu Texas Convicted: 1985, Executed: 1993
Larry Griffin Missouri Conviction: 1981, Executed: 1995
Joseph O'Dell Virginia Conviction: 1986, Executed: 1997
David Spence Texas Conviction: 1984, Executed: 1997
Leo Jones Florida Convicted: 1981, Executed: 1998
Gary Graham Texas Convicted: 1981, Executed: 2000
Cameron Willingham Texas Convicted: 1992, Executed: 2004
http://www.deathpenaltyinfo.org/executed-possibly-innocent