Finalist in the ACT Chief Minister's Export Awards, 2008, recognising my work with the Chinese People's Public Security University, the UNODC and the IMF.
Updated estimates of ML in and through Australia
Some years ago, I was struck by the fact that people would ask me why crime was always increasing, or why crime prevention never worked. Both of these statements, which people clearly believe are universally true, are patently false when you look at the facts. So why is that people are so convinced?
I suspect that there is some "law" in here, but it isn't the simplistic obvious one that people believe in. I would describe this law, mathematically, as:
"Y is linearly dependent on X until enough people realise the implications".
This is illustrated in the diagram below. Let's look at an example. Suppose the X axis is measuring some crime prevention strategy and Y measures the level of crime. As we increase or decrease the level of crime prevention effort, the level of crime should change in response; there should be an inverse relationship between the level of crime and the level of crime prevention effort - as per the red arrow.
The problem with increasing the level of crime prevention effort is that, while it will initially be successful in reducing crime, eventually the offenders targeted by the strategy will realise what they have to do to neutralise its effects, and they will return to their previous levels of offending (the blue arrow on the right). An actual example is that, some years ago, police in Japan installed plastic police officers at accident-prone highway intersections, which succeeded in reducing accident levels - but only until drivers realised that they were being duped.
At the other end of the mechanism, if we reduce our effective level of crime prevention, we can expect increases in crime levels (red arrow moving to the upper left), but only until someone realises the implications, at which point we can expect a "crunch point", followed by a "crisis loop" during which we desperately search for a new crime prevention strategy. An excellent example of this is how traditional family structures in western societies (father at work, mother at home with the kids, extended families living nearby), which contained built-in crime prevention mechanisms, changed in the second half of the 20th century to an increasingly dispersed and motorised lifestyle.
With double-income families living independent lifestyles in "anonymous" suburbs and driving to work and to the shops, these crime prevention mechanisms were lost. Without mother at home, the house became increasingly vulnerable to burglary. While previous generations would not have been comfortable leaving their most valuable possessions unattended in public places, we routinely left our cars and their contents unattended for hours in public car parks. Looking back, it is hardly surprising that rates of burglary and car theft soared in that period.
Then, to everyone's surprise, around the turn of the century, crime levels started to fall in most western countries, and criminologists were at a loss to explain it. Americans ascribed it, amongst other explanations, to their "tough on crime" policies and the extremely long prison sentence imposed by their courts, but neither of these could explain why it also happened across Europe where prison sentences remained much shorter and the extremes of "tough on crime" were never adopted. Professor Jan van Dijk has suggested - with convincing empirical support - that the fall in crime was the result in new forms of crime prevention - more adapted to the modern lifestyle - becoming available. (See "Explaining the Drop in Crime", pages 128-135 in van Dijk, J., "The World of Crime", Sage Publications 2008). Nowadays, we have electronically theft-proof cars, we have cameras and alarms to protect our houses, and we have mobile phones that keep us in contact with our family members and friends. We have replaced our reliance on community inter-dependence by a reliance on electronics to protect us from crime, but it is nonetheless effective.
Walker's Law doesn't just apply to crime and crime prevention trends; it clearly applies, for example, to stocks and shares prices, which will typically increase until enough people think they are overvalued, or decrease until enough people think they are undervalued. It also applies in all fields of public administration, where politicians will act only when enough voters make it clear they are dissatisfied.
It is actually quite an optimistic law, since it implies that, no matter how bad things get, the human race will always find a solution, and the unwanted trends will be wound back. The problem is that, of course, these things take time!
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