Friday, July 18, 2008

BCS BS.

The government have once again been waving around the results of the British Crime Survey to bolster their claims that crime is falling. So I shall, once again, post about why the BCS is not the flawless indicator of crime that the government and its supporters believe it is.

Problems with the BCS:
  • It doesn't cover under 16s, who are proportionately more likely to be the victims of crime than adults.
  • It doesn't cover crimes that aren't specifically directed at an individual, so for example if a school suffers an arson attack or some shops suffer theft then it doesn't show up on the BCS.
  • It doesn't cover crimes against those who aren't permanent residents of the UK, such as tourists or migrant workers.
  • It doesn't cover murder.
  • The sample is not truly random as there are a large number of people who decline to take part and they are concentrated in high crime neighbourhoods.
  • People's recall of what has happened to them over the course of a year is pretty poor.
  • It doesn't cover repeat offences against the same victim, or to be precise it caps the number of offences it records.
Of course the fact that the BCS isn't as reliable as is claimed doesn't mean that crime is rising. With technological advances with cars and mobile phones some crimes are harder to commit than they used to be so robbery is probably down for example. However there is an interesting question as to why people believe crime is rising, it isn't simply, as some newspaper columnists assert because of tabloid hysteria, for example in the USA when crime stats began to fall in the 1990s pretty much everyone accepted that they were clearly true and reflected their day to day experience. The American figures were confirmed by a fall in the one statistic governments can't manipulate, the homicide rate, whereas in the UK the homicide rate has increased substantially over the last decade.

Update: Stephen Pollard writes in the Daily Mail about the BCS's shortcomings.

8 comments:

Daphne said...

Ross, you blog away like a mad brilliant bastard.

I'm in complete awe.

Expect a daily ping from Texas. This site is a brilliant informative sack of wonderfulness with excellent writing smoothing the way. Great job, I am humbled.

Hope you are feeling better.

JuliaM said...

"The American figures were confirmed by a fall in the one statistic governments can't manipulate, the homicide rate..."

Yes, but isn't that rate affected by advances in medical technology? Some of the recent victims of stabbings that have survived have done so due to quick emergency treatment, surely...?

Ross said...

Daphne, Thank you, I hope my sack of wonderfulness is to everyone's satisfaction.

Julia, you are right about that people who would once have been goners now survive. Even so broadly speaking with homicide rates you can be sure of what is being measured.

Umbongo said...

The deliberately BBC misses the obvious: that the BCS is an opinion poll (with all the inherent errors attendant thereto) and that the basis of the "reported crime" statistics has been changed at least twice since 1995 ie there cannot be a respectable comparison between the 1995 figures and the current ones - nor an acceptable time-line of comparison over the 12 years.

I am not surprised that the Home Office would put out a misleading gloss on its performance. Similarly, I am not surprised, but I am appalled, that our "impartial" state broadcaster relays these debatable statistics as if they were the 10 Commandments which Moses had just delivered post his appointment with God on Mt Sinai or (to use a BBC-acceptably inclusive simile) like the Koran delivered by Mo direct from his conference with Allah. In other words, the statistics are sacrosanct - us proles out here have got it all wrong.

Umbongo said...

"The deliberately BBC misses the obvious"

or

The BBC deliberately misses the obvious

Take your choice

John East said...

There is another possibility, assuming the BCS is telling the truth, which I'm not convinced is the case.

Those of us who think prison works would point to the fact that prison population has risen from 64500 in 1999 to around 82,000 today. We would therefore expect a fall in crime as a result.

What really annoys me is the number of hoodie huggers in the Guardian and similar publications who are now saying that because crime is falling it is time to stop sending so many people to jail.

In other words, they are saying that the obvious way to reduce crime that the right have been calling for all along might actually be working, so lets stop doing it.

Mark Wadsworth said...

"Homicide has increased over last ten years"?

And then some! Take a look at page 56 of this Home Office publication.

Ross said...

Mark, I'm having trouble loading PDF files on my computer right now so I'll check it out on Monday.