Airlines say they most often pick trips randomly, and sometimes target problem flights to measure how employees responded to trouble.

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Many law-enforcement officials say that illegal gun-traffickers are most often charged with mere paperwork violations.

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There is a big caveat here: Surveys are not necessarily the most reliable way to measure behavior people often say they do one thing when they actually do something else.

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Messrs Skelcher and Davis's research, which predated the Nolan reforms, also found evidence that the great and the good were to a large extent self-selecting: even in quangos where ministers have the final say, they found that most new members were chosen by the existing board often by personal recommendation.

ECONOMIST: Who��s really who | The