Blackstone and the Balance of Eyewitness Identification Evidence
Blackstone’s Commentaries on the Laws of England is comprised of four books, written in two volumes, running well over 1500 pages in length. Within this enormous work there may be no more well-known or more memorable line than that which has come to be known as the Blackstone Ratio: “the law holds that it is better that ten guilty persons escape than that one innocent suffer.”[1]
The Blackstone Ratio clearly acknowledges that there are two kinds of errors that can be made within the criminal justice system, and that one, the false conviction, is far worse than the other: the false acquittal. Two other points are also implicit within the Blackstone Ratio, specifically that there is a trade-off relationship between false convictions and false acquittals, and the criminal justice system has some control over that trade-off in terms of the kinds of errors, false acquittals or false convictions, it will allow. The implication of the Blackstone Ratio is that the criminal justice system could reduce the number of false convictions, but in the process would lose some correct convictions. Alternatively, the criminal justice system could increase the number of correct convictions, but would likely convict more innocent people as well.
