Perception of value

The Commissioner for Victims of Crime Louise Casey has called for the right to trial by jury to be stopped for everything other than major crimes such as rape and murder. Casey said: "Defendants should not have the right to choose to be tried by a jury over something such as the theft of a bicycle or stealing from a parking meter."

How valuable is a bicycle? Louise Casey obviously thinks that they are cheap, that cycle crime is minor and trivial. But, has she bought a bike recently? Bikes cost a lot more than the money you can get out of a parking meter, with many worth over £1000, more than some cars. Moreover, organised criminal gangs are responsible for stealing thousands of pounds worth of bikes: for their victims, this is not a trivial matter. According to the British Crime Survey, 480,000 bikes are stolen every year.

(Some of the above has come from the Cyclist's Touring Club (www.ctc.org.uk)). For O.R. scientists, her misconception is a warning; make sure that everyone knows (or agrees) the real value of items in your studies. The classic area is placing a value on the cost of inventory. How much does it cost to store one widget for one time period?

Measuring and comparing risks

Yesterday's newspaper had a feature about the risks associated with competing in a triathlon. A study presented to the American College of Cardiology Conference had reported that the death rate among competitors in triathlons was about twice that of competitors in marathons. (1.5 per 100,000 competitors compared with 0.8). That news report closed with the comment from one of the staff at my university that the idea that exercise is dangerous should be compared with sedentary life.

O.R. professionals ought to be able to see through the nonsense of the report and the comment. What are you trying to measure? How do you compare one activity with another? The death rate in the U.K. is about 1 per 100 per year, or 1000 per 100,000. Dividing that by 365 and then by 8, we get 0.35 per 100,000 in a three hour period. So the death rate in marathons (which last 3 to 4 hours for the majority of competitors) is about twice the national death rate. But the rate varies with age and gender and lifestyle. However, the national death rate includes deaths from accidents, which generally affect the more mobile sectors of the population. The people who die outside marathons include the terminally ill, the aged, etc. -- not the sort of people who compete in endurance sport. They probably have an extremely small chance of dying of natural causes in the next three hours. But they have that risk of accident. So we can conclude that the person who decides to enter an endurance sport increases their chance of dying during that event. But the actual risk is still very small; the half-marathon that I mentioned earlier has about 2500 competitors. If the figures for marathons and half-marathons are comparable, there will be an avaerage of one death every fifty years.

But, even more seriously, the reports about when the deaths occur in triathlons, as all but one of those recorded were in the swimming sport, should alert organisers to warn the competitors about the risks of not being prepared for a long, frantic swim in water that is colder than in heated swimming pools.

As for me, I shall cycle home today. My risk of an accident is about 1 in 4000 based on an average of 1 accidents per ten thousand person miles (here) and a journey of 2.5 miles home. (This is about my experience -- I have been hospitalised three times in 40 years of cycling, with an average annual mileage of a little over 1000 miles, giving 3 accidents in 40,000 miles.)

Operational Research and Design

One of the subject headings in the International Abstracts in O.R. (IAOR) is "Design". Over the years, there have been comparatively few abstracts which were classified under this heading. I wondered why. What sort of papers would be classified as "O.R. in Design"? One tends to think of design in connection with small (comparatively) items or matters, when one is not concerned with aesthetics. Things like household equipment, the layout of roads, small engineering items. A useful text is The Design of Everyday Things by Donald A Norman -- which doesn't mention O.R. but does discuss optimality quite frequently. But this aspect of design does not lead to academic papers. Manufacturers employ designers to make money, not to produce learned papers. Look at the jets in the rotor of a dishwasher; someone has designed them, found the best angles, positions and sizes, in order to efficiently and cheaply carry out a dishwashing cycle. Hard work -- hard O.R. work -- but not worth writing about. Sometimes the results of design are commercial secrets. When I was recently out of my postgraduate training, I went on a site visit and asked about a piece of equipment on the production line. Had the company patented it? No, because a patent would be visible to their rivals.

But sometimes one wishes that the results of design as the result of a modelling process could be made public. By doing that the benefits of one person's analysis could be usefully shared. I come across such an example regularly. What is the optimal separation between cycle racks? By the swimming pool, there are six racks, at 45cm apart. The outermost racks are therefore 225cm apart, and one can park seven bicycles in the space. Near the office, there are four racks, 100cm apart. Two bikes can be parked in each gap, so in 300cm there are eight bikes. Which is better?