Use and abuse of statistics

Sir, – I commend Fred Cummins for his letter (August 14th) about the misuse of simple percentages, though I must say this failing is not confined to journalists. Politicians and others are equally at fault for the spurious use, or misuse, of statistics. A common misconception is that, because an increase from 100 to 200 represents an increase of 100 per cent, a decrease from 200 to 100 is a decrease of 100 per cent. It is no such thing, rather a decrease of 50 per cent. A decrease of 100 per cent always results in zero. A 100 per cent decrease from 200 produces zero, as does a 100 per cent decrease from one million, or any other figure. – Yours, etc,

PADDY LYONS.

Somerby Road,

Greystones,

Co Wicklow