The UK's summer riots this past August which started in London has attracted much comment and analysis. A common remark is that previously convicted criminals were largely to blame.
This is a convenient political cover for at least two reasons:
1. It is easier to get data to support the analysis.
The police have access to technologies that assist in facial recognition of persons in crowds. Of course, - in order to be recognised - you must be somewhere on the system first. Non-criminals without any past record would be less likely to identified either through the use of technology or by police looking over scanned images. In fact, it would probably be surprising - given the numbers of people involved in the riots - if the great majority arrested and convicted lacked convictions. This is because those with previous convictions are easy to pick out and not because they were a majority.
2. It is easier to shift the blame.
If the problem is general criminality (and inherited criminality), then the government can try to claim they were not at fault.
3. The data is incomplete.
There have been several figures offered on how many took part in the riots. According to most figures I have seen, the great majority of those involved in the riots have not been arrested nor convicted. If the great majority involved are persons generally unknown, then we only know something about that smaller set of persons who have been arrested and convicted: our judgements based on such information are liable to offer a misleading picture as a result. Perhaps most convicted had previous convictions, but why think that this must also be true of most others (others who are "unknown")? It makes far more sense to take the view that the reason why the majority convicted have been found to have previous convictions because those with previous convictions are already known and easier to identify. When the government claims that most involved in the riots had past convictions, they really mean that persons with past convictions were easier to find, but we don't know the full picture until far more involved are identified.
4. Will it matter?
I doubt many will pay much attention to this except for police officers, criminologists and anyone with a serious interest in this issue at the Home Office. Politicians should always know that there is (a) what you say to communicate your message and (b) what you do to better prepare for future events. We have had (a), but now time to turn to (b). One worry is that the government will believe its own message and think that it has "dealt" with the problem, but I suspect it is long from over both in terms of identifying others involved and also addressing the original situation - and context - that have rise to the riots in the first place.
Problems seek solutions, and few come quickly.