Well, has it risen, or not?

Crime, that is?

The short answer is that it is difficult to say.

In the first place there are two ways of measuring the rate of crime:

1) Police Records, aggregated. This series has been collected for several years, but there have been changes at intervals which make comparisons over time very difficult. Recently the accuracy has been improved to give a clearer total of crimes reported to the police. This showed an increase in reported crimes, and consequently was ignored by the Government - perhaps they were right.

A major problem here, of course, is that the public have become so disappointed with police response that many have given up reporting all but the most serious crimes.

2) British Crime Survey. This is a (sample) survey, asking people about their experiences. It has all the difficulties associated with surveying and sampling. Recently the Government have given greater prominence to this, as it seems to support their contention that crime is falling, although when in opposition they were very critical, but if the Police Reports seem to be more favourable there is little doubt that this measure would be emphasised.

The problem here is that crimes by those aged under 16 are ignored, and by other categories such as businesses. Some crimes are not considered, and for any respondent only a maximum of five repeated offences for any particular crime are considered. There is likely to be considerable under-counting.

Aggregation, crudely putting all areas and all offences in a simple numerical total, can cause problems. Is the theft of paper clips to count as the same as a bullion robbery, a stabbing, fraud, drunken driving racial incitement, etc. Usually some attempt is made to distinguish - "Crime has fallen by 5%, overall, but violent crime has increased by 10%." Any summary measure has to have values or "weights" attached to particular results to average everything out. Just how many paperclips would have to be stolen on how many occasions to neutralise a change in the opposite direction to changes in speeding offences?

Given everything I have written, no figures by any politician of whatever party or by civil servants on their behalf should be taken without asking how they have arrived at the figures.