Through repeated trials, the manager keeps tweaking the approach until its phantom record is as good as possible.

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Watching repeated trials of the system is Admiral Lord West of Spithead - the Home Office's counter terrorism minister.

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Repeated trials are likely to be better than one-off experiments in this respect: people make fewer straightforward mistakes at the end of 20 reps than at the beginning.

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This was despite repeated clinical trials which have found that homeopathic medicines - which contain heavily diluted traces of the substance causing the illness - are ineffective.

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But Angers prosecutors said there were telling differences between the trials, and expressed confidence that the mistakes of Outreau would not be repeated.

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