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The irresponsible representation of IQ tests as "scientific" on the BBC's Test the Nation raises serious professional and ethical issues (Features, THES, May 10). The measurement of "intelligence" by a single number called IQ has been largely discredited, and comparisons using tiny differences are meaningless. The show did participants a grave, and potentially damaging, disservice by encouraging such comparisons.

Len Fisher

Honorary research fellow in physics

Bristol University