A story in today's New York Times raises an interesting question: What is more important, getting a conviction in a criminal case, or protecting the innocent against false accusations?
It turns out that new procedures in the identification of suspects by way of police lineup are resulting in fewer positive identifications of suspects, and more identification of innocent people as perpetrators.
The traditional simultaneous lineup procedure involved placing a group of suspects before a witness. By comparing and contrasting the suspects, a witness could ponder which person, if any, was the perp. The danger in the procedure was the subtle assumption that at least one among the group was correct. Rather than picking the right person, the wtiness was feared to pick the one who looked most like the perp.
Reforms in lineup procedures require that witnesses be shown one photo at a time. And these photos are shown in such a way as to limit or eliminate subtle sources of selection bias law enforcement officers may signal in the procedure.
The results have been disappointing: fewer positive identifications, and, when there is an identification, more misidentification. In a controlled experiment in Illinois, witnesses chose the correct person 60 percent of the time using the simultaneous method, as opposed to 45 percent of the time using sequential lineups. The wrong person was picked 9 percent of the time using sequential lineups, as opposed to 3 percent of the time using simultaneous procedures.
So now the debate will renew: Should we retain the simultaneous lineup?
The data suggests we might want to consider scrapping both. The Times reports that each year 77,000 people are put on trial as a result of lineup identification. That number seems too high. I doubt there are 77,000 criminal trials in the country in a given year.
But if 77,000 people are charged as a result of lineups, a claim that seems more likely, then with simultaneous lineups, we are charging the wrong person 2,310 times; using sequential lineups, the wrong person is charged 6,930 times. That's hardly reassuring, unless our goal is simply to close files with arrests.