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Published online 2 February 2009 | Nature | doi:10.1038/news.2009.73
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Racial profiling methods may be flawed
Screening by ethnicity could be allowing more criminals to slip through the net.
Singling out individuals for surveillance, investigation or screening on the basis of their race or nationality is probably useless for catching those engaged in or planning criminal acts. That is the conclusion of a computer scientist who has exposed the basic mathematical flaw in this approach to crime prevention.
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I must have missed something in the reading. If innocent individuals are wrongly selected repeatedly,a type 1 error, how does that relate to the selection success rate. That is, is there any data on how well actuarial selection can select a person with criminal intent? I assume that by criminal intent that the article means intent to cause violence related to the unrest in the middle east but I don't know if the article is referring to other crimes like drugs or running red lights.
Why should it make any difference how many innocent passengers are wrongly selected if the TSA's methods, which may include ethnic profiling, actually select guilty passengers? It is the selection of guilty passengers from the entire population that is important. While an inconvenience for those innocent passengers selected, if profiling has been TSA policy that for the last seven years has resulted in no additional buildings targeted by terrorists on airliners, then we are better defended because of it.
I assume that 'doing the math' refers to comparing the vast numbers of individuals of any ethnic group who are peaceful and law-abiding to the very small number of those in each group with criminal intent. The larger the overall size of the group, the less effective screening will be, and, if targeted, the more resentment will build. Q: Do those of Western European descent consider themselves an ethnic group? I think probably not, and therein lies a problem.
Frightening display of (twisted) intellectualism in what can only be called "deconstructive logic." The underlying premise (ethnic profiling is statistically worthless) is a misleading premise. The current efforts to stem terroristic behavior is not predicated on taking red and black balls out of a bag. It is an hugely complicated effort that must rely on using an evolving set of filters, the most important of which remains the unappreciated TSA agent standing for hours at an airport watching an endless queue of potential suspects.
"Why should it make any difference how many innocent passengers are wrongly selected if the TSA's methods, which may include ethnic profiling, actually select guilty passengers?" Because for each innocent passenger you select (unles you actually screen everyone), that's one less guilty one you can screen. If in a population of 100, there's 2 guilty parties and 98 innocents, if you only get to select 10 people, you don't want to be choosing 9 innocent ones.
Apart from the problems mentioned in the article (alienating a large population of otherwise law-abiding people, leading some of them to become more likely to engage in illegal activities), one of the biggest problems with profiling is that it lets real criminals through. The false positives are accompanied by missed identifications. The people providing the security services are doing so with finite means. As Marc A. Bélanger notes, you can closely screen a only small percentage of all the passengers coming through an airport terminal (or customs port, or whatever), so you have to make good choices about who those people are.