Sunday, March 4, 2007

More from Munsterberg: Accuracy & Choosing Rates, and New Tech

Highlights from the last day and a half include a new meta-analysis of nine studies, charting variables including cross-race, weapon-focus, and the ongoing simultaneous vs. sequential debate, presented by Stephen Ross.

Dr. Ross's central suggestion for future research was the crafting of meaningful ways of distinguishing between "ground accuracy" and suspect choosing rates, when comparing the effectiveness of different presentation procedures used in field studies. Little attention has been paid to the distinction, and yet field study after field study purports to compare the "accuracy rates" of simultaneous and sequential procedures. All these studies actually reveal are suspect choosing rates, and in all but 3 studies, according to Dr. Ross, no attempt was made to assess what he termed "ground truth" -- i.e., whether or not the suspect actually was the culprit, which would seem to be the ultimate question. Ross urged scientists to focus on using reliable methods (e.g., DNA) to corroborate guilt, in order to give more weight to findings that rarely show more than the likelihood that a witness will choose the police suspect. In the same study, sequential lineups were again shown to result in a higher percentage of suspect picks, but with a lower pick-rate overall.

Another set of talks was presented by Otto MacLin and his crew from the University of Northern Iowa, on using technology to advance lineup reforms. Dr. MacLin developed a software application called PC Eyewitness, which in its latest PDA version allows law enforcement officers to take photos of suspects in the field, transmit descriptive information to a central server, and perform "centralized lineup construction," using statewide databases. The technology itself is fairly straightforward, but in a field that is otherwise behind on the technological front, this appears as an important development toward the end of standardizing procedures and minimizing suggestivity in the field.

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