Having established the reality of his point, he then designed a mathematical model that tried to take into account and quantify sources of error.

ECONOMIST: Just how reliable are scientific papers?

Some sources of potential error have been known for a long time (for example, because of slight changes in their orbits, satellites do not always take temperature measurements at precisely the same time of day).

ECONOMIST: A heated controversy | The

Sources close to Mr Blunkett said he had made the error during a 1995 party conference speech.

BBC: Grammar debate is a 'past agenda'