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Sunday 31 January 2010
Getting back to my discussion of fear of crime. I have explained what the dark figure is and hinted that it can be measured. This is done by victimisation surveys. The British Crime Survey is carried out to provide this and other information by questioning members of the public about their experience of crime and disorder and the police. Through statistical sampling techniques and extrapolation an independent count of crimes that have individuals or households as victims can be calculated. This count is then compared with the police recorded crime figures. Logically the BCS figures should be higher than the police recorded crime figure because, as I have discussed, not all crime is reported or discovered by police and even if it is it is not necessarily counted. The difference between the two sets of statistics therefore is a measurement of the dark figure.
The dark figure can be expressed as a percentage of "total" crime. This percentage varies with different types of crime. For instance theft of vehicles have a low percentage due to the necessity to report the crime to police before making an insurance claim whereas sex crimes tend to have a large percentage dark figure.
Friday 22 January 2010
The MPS announced yesterday that crime is at its lowest level for 10 years. The details can be found here. They omit to include "recorded" in front of crime; an error in my view.
I have a couple of brief comments to make.
(1) Despite the overarching performance indicator being confidence in the police recorded crime statistics are still very important to the police. Probably more internally than externally. It is a performance indicator that makes or breaks promotion ambitions (in theory but probably not in practice). I am not totally against this but it does mean that good "housekeeping" can reduce recorded crime by ensuring only those allegations that have to be recorded are. This is like trying to ring a flannel dry. A portion of recorded crime reduction is due to evermore innovative ringing techniques.
(2) The MPS seem happy to take credit for the lowest level of crime for 10 years. I think this is the wrong approach. The influence police have on crime figures is an area of ongoing research, my own included, with no definitive conclusions. What is known is that crime has many causes a lot of which are out of the direct control of police therefore in my opinion, and consistent with Neighbourhood Policing, a more partnership approach thanking the efforts of the communities in London would strike a better tone.
Credit is what other people give you, not what you try to grab yourself.
Wednesday 20 January 2010
First there is what criminologists call the "dark figure". It is a bit like the way in which 19th century explorers referred to the Dark Continent of Africa. We know its there, we have an idea of what it looks like, we may even have an idea how big it is, but to a large extent it is uncharted territory. The dark figure, in its most undefined sense, is the difference between the crime that occurs and that which features in official crime statistics.
Now we then get into the sticky problem of what is a crime anyway. We will park that to one side for the moment because I could write numerous quite technical blog entries on that subject alone.
In England and Wales a crime in its most narrow sense is an offense that Home Office police forces are required to tell the Home Office about so the Home Office can compile their official statistics. These are known as notifiable offences. These are mainly offences that involve theft, violence or of a sexual nature or drug related. Importantly, antisocial type behaviour such as drunkenness, begging and littering though against criminal law are not notifiable offences. Equally road traffic offences, except the most serious, are not either.
Next we come to Home Office counting rules. These are no doubt very logical but fiendishly boring. Suffice to say that even if a notifiable offence has occurred the times it is counted as having occurred varies with the circumstances in which comes to police notice. For instance, from memory, and it might have changed (one of the problems of comparing year to year official recorded crime), if a series of the same crime has occurred in the past with the same victim and it is the first time it has come to police notice then that is counted as one crime. But future crimes, if reported to police individually, are counted separately.
So we have now got an idea of a narrow set of crimes, but to be fair include all the serious crimes, and a rigid set of counting rules. The dark figure in its most defined sense are those crimes that would have featured in the official statistics but do not because the police did not discover them or more commonly were not reported to them by the victim or other person.
Ok, so that's the dark figure.
Tuesday 19 January 2010
The RG is the difference between police recorded crime figures which were going down and what people perceived to be the case, which was crime was a bad as ever, in fact it may even be going up.
The Reassurance Policing Programme (RPP), started in earnest in 2004 was set up to address this problem. Since then the emphasis in government and policing policy, and academic literature has been on reducing the fear of crime. It seems to be accepted now without any real thought or discussion that the fear of crime is a bad thing that we should be getting rid of it.
Taking a step back though we can see that in every other sphere of life fear has a positive aspect. It is what keeps us out of dangerous situations, it what helps us make sensible decisions, its what keeps us alive.
One of the interesting aspects of the fear of crime is that it seems that the people that are apparently most at risk, young males (see my street robbery analysis posts) are the least fearful and those least at risk, the elderly, are most the fearful.
Risk has two aspects though, probability and consequence. This is where lifestyle and vulnerability come in. Young males to a large extent are victims because of their risky lifestyle which is a result of a feeling of a lack of vulnerability. Most take being a victim of crime in their stride as long it is not too serious. Elderly people on the other hand tend to cultivate a risk averse lifestyle due to their feeling of vulnerability because the consequences of being a victim of crime, even relatively minor, tends to be far more serious.
That is the reason why so called distraction burglaries (or burglary artifice to use the policing term) is such a nasty, despicable and serious crime. Its criminals target elderly people in their homes and rely on faulty memory and sight, and engendering a feeling of guilt in their victims that they have been stupid, to get away with it.
Crimestoppers have quite rightly made this type of crime a priority and published a list of the 10 most wanted. Have a look here you may be able to help.
Sunday 17 January 2010
Friday 15 January 2010
I tend to like my crime data how I like my caviar, raw and with good provenance. The new data store referred to in my previous post has raw as well as mucked about data. And the provenance is not always clear.
I present the three maps above more to make a point than to illustrate facts because I do not know how the numbers of alcohol attributed violent crimes are calculated. I assume they are based on police recorded crime but because the figures are not integers I assume some sort of sampling has taken place.
The point I wish to make is using the raw data is valid in my view so the top map gets a tick. Alcohol attributed violent crime must be hugely influenced by non-resident populations so in my view the second map is meaningless. The third map is a result of me putting together two datasets from the London Data Store. I am using the number of bar employees as a proxy indicator of the number of alcohol outlets there are in each borough because I think it is reasonable to assume that the alcohol attributed violence is connected with people who have frequented such places. Therefore I think my map is better for comparison purpose.
PS I don't eat caviar... but the point about crime data remains.
Monday 11 January 2010
What I have here is a map visualisation of an exciting new data source that Alex brought to my attention. It can be found here. I have not had a chance to have a look through it all but this one looked relevant to crime. So I quickly mapped it using ARCGIS.
Wednesday 6 January 2010
I hear on the news that police in affected areas are trying to hire 4x4 vehicles and are only attending life and death type emergencies.
The question is does snow influence crime. Logically it must do, peoples' behaviour changes, they stay at home. It seems though that not all of London is equally affected. Fabian has reported that London this morning was a ghost town, not because it was white with snow but because there was hardly anyone around.
There is an interesting paper in the September 2009 issue of the academic journal Environment and Planning B entitled "The influence of weather on local geographical patterns of police calls for service." This did not specifically investigate the influence of snow but does show evidence of that high temperatures increasing violent crime and high temperatures and humidity affecting the geography of disorder.
The problem with this type of study is firstly obtaining detailed temporal and geographical details of the weather and secondly determining the extent of geographical and temporal influence of the weather. For instance, as we have seen, snow influences areas where it has not snowed, so comparing the part of London where it has snowed to where it has not snowed will give only a partial answer. Equally the affect of snow lasts till it melts rather than just when it falls.
It would interesting to do a brief analysis on these few days to see how crime/police incident patterns change. Hopefully this will not be considered pointless research like that conducted on penguins presumably in the snow!
Tuesday 5 January 2010
Monday 4 January 2010
Returning to the analysis of street robberies in a London borough. I have established that street robberies occurred more in certain locations and times than others; that certain people are more likely to be victims and/or offenders than others. Even that times and locations and types of victims are linked. I have also shown that even though these elements of the crime commission process are non random the actual occurrence of crime at a specific location within a broad time frame (that eliminates to a large extent cyclic processes) is random.