Friday, 1 April 2011

Lap dancing and rape in Camden: part 4

Read all the posts in this
[1] [2] [3] [4] [5]

Another problem with the original paper is a lack of an appropriate control population, to compare the results with. Having a control population is particularly important in assessing risk. Controls are populations where the thing you want to test – strip clubs, in the case of the Lilith report – doesn’t exist, for comparison purposes.

For instance, in order to suggest a link between smoking and lung cancer, the original epidemiologists had to examine lung cancer rates not only in smokers, but also in non-smokers. You need to show that the factor being examined - smoking, or in our case, lap dance clubs - is the influencing factor.

Lack of a control group means that the numbers of rapes in Camden were not reported against the rape stats in a non-lapdancing area. It’s perfectly possible that the trends happening in Camden were happening everywhere, regardless of whether there was lap dancing or not. It’s impossible to know from the Lilith study if such other parts of London were experiencing similar trends in their crime rates.

The report makes comparisons between Camden, Westminster and Islington, all of which contain lap dancing clubs. As far as control populations go, that’s no good: you need somewhere where it doesn’t happen. Kind of like a placebo group in a medical trial.

So let’s run the statistics using Camden, one of the other areas they pick which does have strip clubs, and choose an additional one that has none at all. Because crime can be influenced by factors such as poverty, it would preferably be of a similar demographic profile. Then an assessment of the occurrence of rape in that area can be made, for comparison’s sake. Without doing this, it’s impossible to say whether any trend was locally concentrated or happening everywhere regardless of strip clubs.
Lambeth has a somewhat larger population than Camden and similar makeup in terms of ethnic origin. It contains no lap dancing clubs at all. Islington has a somewhat smaller population than the other two boroughs and has two venues licensed for fully nude lapdancing. And since these statistics are also available for the entire country, let’s throw that in too. After all the original claim was that Camden's rape stats were three times the national average.

Comprehensive statistics are available for crimes reported to police throughout England and Wales, so these are straightforward to find.

I shan't bore you with another table, though of course, those numbers are available (both from me and from the Metropolitan Police) if you're interested. It pains me to leave one out, because I love tables like a fat kid loves cake. But one woman's cakey feast is another's sugar rush nightmare, so. Let's skip straight to the graph. Again, the years covered by the Lilith paper for Camden are highlighted in red:

The graph shows that adding comparison changes the picture considerably. It no longer appears that lap-dancing clubs lead to an increase in rape, since boroughs with fewer or no clubs had consistently higher rates than Camden’s. The data from the original study is shown to be a small blip in a larger – downward – trend all over London.

If there was a relationship between the number of lap dancing clubs and the occurrence of rape, you would expect Lambeth to be lowest of the three because it has no clubs. Islington would be higher because it has a couple, and Camden highest because it has more than those other boroughs. But Camden turns out to be the lowest of the three. There does not appear to be any relationship between the number of lap dancing clubs in a borough and the risk of rape.

The trend for the three London boroughs shows clearly that Lambeth (with no lap dancing) and Islington (with only 2 clubs) both have rates that are higher than Camden’s. All three have decreased over time, as well, which is why it pays to look at the longer trend rather than cherry-picking a few years in statistics. Apart from the early 2000s peak, Camden’s numbers are close to the overall rate for England and Wales, and are sometimes even below it. This is a far cry from the “three times the national average” claimed by the Lilith report.

All things considered, you might wonder why the Lilith report chose to look at Camden at all. According to the introduction, it was because “Lilith and Eaves believe that Camden’s opinion and acts carry great weight with other London boroughs.” Which from the analytical point of view (especially considering there are no references or other reasons given) doesn't make sense.

If we were to take this graph as our only evidence, we might conclude that the risk of rape goes up not because of the presence of lap dancing clubs, but by living in London, with Camden actually safer in that regard than other boroughs. We might also be tempted to conclude that the presence of lap dancing clubs in fact indicates a safer borough in terms of rape.

Naturally, that would be a very rash conclusion, something a responsible statistician would be reluctant to suggest. It would require far more data from the rest of London and the entire nation before such an idea could be suggested. But that’s the point – in order to make a conclusion about the effects of social phenomena in general, you need a huge amount of information to back it up. One limited study of a crime statistic is not enough and should never be allowed to stand on its own.

Interestingly enough, there are other places where the opening of lap dancing clubs does seem also to correspond with a reduction in rape and assaults. One of these is Newquay, in Cornwall.

In 2010, local paper Newquay Voice obtained Devon and Cornwall Constabulary’s figures of sexual assaults. They found that the total number of recorded sexual assaults (including rapes) in and around Newquay peaked at 71 in 2005, the year before Newquay's first lap dance club opened. In 2006, the year following its opening, the number fell to 51.

In 2007, when the town’s second lap dancing venue opened, the total number of recorded sexual assaults fell again to 41, then dropped to 27 in 2008 when a third lap dancing club opened. In 2009, the number rose slightly, but with a total of 33 offences, it is still less than half the total than before the clubs appeared. Here are the incidence rate calculations (using midyear population levels for the council of Restormel, where Newquay is located):

Again, this is only a single example – to conclusively demonstrate that an increase in lap dancing corresponds with a decrease in rape and sexual assault, there would have to man more such results, over longer time periods, from many places. However it does reinforce the same thing the statistics from Camden show: that lap dancing definitely does not correlate with higher occurrence of rape. And if there is no rise in rape, then it is impossible to claim that lap dancing “causes” rape.

Rape is widely thought to be a vastly under-reported crime. The calculations don’t tell us whether rapes were under-reported for the area in any particular year, nor what might cause that.

What it does tell us is that the original claim made in the Lilith report – that the number of reported rapes is rising – is not true. It was not true in 2003, it continues not to be true, yet the myth that rapes rise 50% after lap dancing clubs opened in Camden is still reported, even as recently as August 2009.