Lies, damn lies and statistics

That old saying of Benjamin Disraeli came to mind when I heard that the Labour government were claiming that figures showed that knife-crime was down. However I almost went into shock when the BBC Radio 4 6 o'clock news laSt night had a piece on how the figures may not be worth the paper they were released on. Mark Easton's blog has some details on this including the line (my emphasis)

"the new numbers are not official crime statistics. They will not be published by the Office for National Statistics, which is independent of government and supposedly ensures figures are free of political spin. Instead, the Home Office has rung up police forces and asked them for statistics to illustrate the effectiveness of their "Tackling Knives Action Programme" (TKAP).

"Serious knife crimes against young people (homicide, attempted murder, GBH with intent) fell by 17% between June and October 2008 in the ten TKAP areas," the Home Office press release proclaims.

Sounds good. But 17% actually equals, er... 17 incidents. In June, there were 98 serious offences. In October there were 81. In fact, the Home Office confirmed to me this afternoon that in September, there were only 68.

This is statistical nonsense. Some papers may like to proclaim tomorrow that knife crime has "soared 19%" on the basis of the figures from the latest two months. But this would be equally misleading. When you get down to such small numbers, percentage change doesn't mean much.

And comparing figures month on month is also questionable, because crime is seasonal. Gangsters don't go out so much when it gets cold....

Odd to choose April to September, when their scheme only really got going in July. Sceptics might think this has something to do with the fact that recorded knife crime was already falling before their scheme. "

Do read the rest of the article and wonder if "statistical nonsense" should be the tag-line for this Labour government and Gordon Brown in particular.