To people in Britain born before -- say -- 1955, the name "Doctor Beeching" automatically conjures up the story of the drastic curtailing of the UK railway network. Following a study of the financial health of the UK railway system, in the early 1960's, Doctor Beeching recommended the closure of many railway branch lines and many stations on the remaining lines. From a network which connected cities, towns and villages, the network became one which connected cities and large towns. The report envisaged rail users commuting to their nearest station by car or public transport, and continuing their journey by rail. Over the years, the Beeching closures have been condemned by many people. Unfortunately, it is very difficult to reverse them; old tracks have been taken up, and the land has reverted to farmland or used for housing. Some stretches of the network have become footpaths and cycleways.
Last week, proposals were published to try and reverse some changes, by reopening lines and reinstating stations. Intriguingly, the proposals were based on a cost-benefit analysis, and the proposals were those which exceeded a threshold for the ratio of costs to benefits. So O.R. was used, at least in the financial model. Two cheers for the report! It would get three cheers, if there was evidence that the compilers had looked at the feasibility of the proposals, asking questions such as the availibility of car-parks for rail users, and whether or not timetables could be adjusted to include the new stations and lines.
Monday, 22 June 2009
Digital Britain
Last week the UK government launched a programme based on a report titled "Digital Britain". The aim is to develop the electronic infrastructure of the UK in the next decade or so. The news media have homed in on three proposals from the many (an executive summary of 30 pages seems to go against the desire to be concise). One relates to the funding of the national broadcasting services (BBC), one to the funding of the national broadband network (so every home can have 2MBps broadband by 2012) and the third to the desire to move many FM radio transmissions to Digital by 2015.
Let's look at the second and third from an OR perspective. The proposed funding scheme is a tax of £6 per year on each telephone landline in the UK. (It's not clear if this will be applied pro rata for businesses with internal exchanges.) The media have questioned why such a tax is needed. The government scenario is that the objective of extending the broadband service can only be done by government intervention. An alternative scenario is that commercial operators will develop the broadband provision in response to demand and their financial objectives. So far the operators have done very well without the need for taxes to help. And with the increasing convergence of computer technology and telephone technology, is the scenario seen by the government the correct one?
The third proposal is intriguing. Digital radio in the uK is often referred to as DAB-radio. The government argues that the cost of upgrading the FM network will be about £200million, and this is not worthwhile. Instead, they are looking to manufacturers to develop radios that cost less than £20. So, instead of spending £200million, consumers are expected to replace their radios. Currently, our home has 7 FM radios, plus one in the car. All of these have other functions -- a radio alarm, radios with CD players, an MP3 player with FM radio. So, to replace these will cost rather more than £20 each; unlike TV sets which often have a limited life, radios go on and on and on. Of our 7 household radios, I expect 5 or 6 to be in working order in 2015. Is the scenario of scrapping them a good one? I don't think so.
Finally, the report was launched with a triumphant "We want the UK to be the best in Europe or the world". What about helping other countries to develop in their use of technology? Do we selfishly optimise our bit of the system, or do we think globally and optimise the whole? I favour thinking globally, even if it means that the UK infrastructure is not quite the best in the world!
Let's look at the second and third from an OR perspective. The proposed funding scheme is a tax of £6 per year on each telephone landline in the UK. (It's not clear if this will be applied pro rata for businesses with internal exchanges.) The media have questioned why such a tax is needed. The government scenario is that the objective of extending the broadband service can only be done by government intervention. An alternative scenario is that commercial operators will develop the broadband provision in response to demand and their financial objectives. So far the operators have done very well without the need for taxes to help. And with the increasing convergence of computer technology and telephone technology, is the scenario seen by the government the correct one?
The third proposal is intriguing. Digital radio in the uK is often referred to as DAB-radio. The government argues that the cost of upgrading the FM network will be about £200million, and this is not worthwhile. Instead, they are looking to manufacturers to develop radios that cost less than £20. So, instead of spending £200million, consumers are expected to replace their radios. Currently, our home has 7 FM radios, plus one in the car. All of these have other functions -- a radio alarm, radios with CD players, an MP3 player with FM radio. So, to replace these will cost rather more than £20 each; unlike TV sets which often have a limited life, radios go on and on and on. Of our 7 household radios, I expect 5 or 6 to be in working order in 2015. Is the scenario of scrapping them a good one? I don't think so.
Finally, the report was launched with a triumphant "We want the UK to be the best in Europe or the world". What about helping other countries to develop in their use of technology? Do we selfishly optimise our bit of the system, or do we think globally and optimise the whole? I favour thinking globally, even if it means that the UK infrastructure is not quite the best in the world!
Monday, 1 June 2009
How not to display data
In an earlier blog, I quoted one of my email signatures which uses the following quotation:
In the information age, somebody has to specialize in the development and presentation of really useful information. Doing that for management and decision-making applications is the core role of Operational Research scientists. (Randy Robinson, the first executive director of INFORMS)
Ever since I read the books "The Use and Abuse of Statistics" and "How to Lie with Statistics" I have been alert to examples of poor communication of data. Today's example comes, I am afraid, from my own university (Exeter).
Here is a map showing the modes of transport used by a sample of employees of the university. I am not sure whether to point the finger at the university or Devon County Council. So what's wrong? A few thoughts to start with.
1) The map covers far too great an area; there should be enlargements around Exeter.
2) The symbols are horrible. A black parenthesis on top of a coloured exclamation mark.
3) When you magnify the map to see the detail (and in most cases, to see the colour) then the symbols are lost.
4) What is the point? Is it to inform?
Let's be positive: could the information be presented in a different way? Suppose that we separated the modes of transport to see where the walkers come from. And those who use public transport? And those who car share? And those who travel less than 2 miles by car? The maps for many of these could be on a large scale. Then we might apply some contours of equal travelling time. But we still haven't answered the question "what is the point?"
In the information age, somebody has to specialize in the development and presentation of really useful information. Doing that for management and decision-making applications is the core role of Operational Research scientists. (Randy Robinson, the first executive director of INFORMS)
Ever since I read the books "The Use and Abuse of Statistics" and "How to Lie with Statistics" I have been alert to examples of poor communication of data. Today's example comes, I am afraid, from my own university (Exeter).
Here is a map showing the modes of transport used by a sample of employees of the university. I am not sure whether to point the finger at the university or Devon County Council. So what's wrong? A few thoughts to start with.
1) The map covers far too great an area; there should be enlargements around Exeter.
2) The symbols are horrible. A black parenthesis on top of a coloured exclamation mark.
3) When you magnify the map to see the detail (and in most cases, to see the colour) then the symbols are lost.
4) What is the point? Is it to inform?
Let's be positive: could the information be presented in a different way? Suppose that we separated the modes of transport to see where the walkers come from. And those who use public transport? And those who car share? And those who travel less than 2 miles by car? The maps for many of these could be on a large scale. Then we might apply some contours of equal travelling time. But we still haven't answered the question "what is the point?"
Wednesday, 27 May 2009
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.)
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.)
Monday, 18 May 2009
Displaying data provocatively
For many years, I have been interested in the potential for using O.R. in developing countries. By a process of serendipity, I have just discovered Gapminder, where data about the world's nations are shown in original and challenging ways. I wish that I had discovered the site before now!
Wednesday, 13 May 2009
Spreadsheets and O.R.
The journal Interfaces from the U.S. O.R. Society (INFORMS) is one that I have always enjoyed reading. It describes itself as the "Journal on the Practice of Operations Research" and has often published detailed descriptions of case studies. Older members of the O.R. community will recall that for many years it was edited by Gene Woolsey, and he contributed anecdotes about his practical experience; it wasn't always the received wisdom of O.R. academics, but it was based on genuine experience of getting ones hands dirty doing our discipline.
The March-April 2009 issue of Interfaces has arrived (it takes time to cross the Atlantic) and includes an article "How Electronic Spreadsheets Changed the World" (Rick Hesse and Deborah Hesse Scerno). There was a great deal to which I could relate, as we ran a spreadsheet modelling course in the degree programme in Mathematical Statistics and O.R. at Exeter University. (From the launch of the programme, we taught students to write simple programs in Fortran, then Pascal, Simula and Smalltalk. I recall telling applicants that we expected them to use computers as a tool to help them solve problems, so we stressed a thoughtful approach to programming, and the willingness to use computer packages sensibly.)
Spreadsheets came on the scene in the 1980's -- and provided many companies and individuals with a reason for buying a personal computer. Then spreadsheets were used in schools, with the result that university entrants and others joining the job market had a basic knowledge, often of Excel. But that basic knowledge did not extend to much model-building. We found that we needed to share ideas from computer programming with students in order to help them build appropriate models. As the article emphasises, spreadsheets are wonderful -- used in the right fashion. And O.R. people need to recognise that their fashion is different from that of other professionals, and so their spreadsheet skill set needs to be honed suitably. And that takes time!
Tuesday, 5 May 2009
Running a sponge station
Google can't find the expression "Running a sponge station", so this is a first!
On Sunday 3rd May, our church ran a sponge station for the Great West Run, which is Exeter's half marathon. You can see our church at 1:41 on the video, and just glimpse some of our sponge station roadies in the next two seconds.
Our job was to hand out damp sponges to runners as they passed, and we were equipped with cheap sponges, bins for water, tabards to wear. After that, we were on our own. With experience from 2008, we had buckets and large jars for water as well, and the church tap was running continuously to refill the bins. We needed a team to collect discarded sponges, which were then washed (my job) and returned for reuse as the runners passed the church four times!
There is an assignment problem here, dealing with the varied jobs that need to be done; moving water, collecting sponges, washing, handing out. Unfortunately, it is a messy problem to solve. I don't know the skills of the volunteers, and the demands on the team in fiture will depend on the weather! So, like so many messy problems, it was solved dynamically, as each of us who could transferred between tasks as required.
At the end, we had shown God's love for the community.
On Sunday 3rd May, our church ran a sponge station for the Great West Run, which is Exeter's half marathon. You can see our church at 1:41 on the video, and just glimpse some of our sponge station roadies in the next two seconds.
Our job was to hand out damp sponges to runners as they passed, and we were equipped with cheap sponges, bins for water, tabards to wear. After that, we were on our own. With experience from 2008, we had buckets and large jars for water as well, and the church tap was running continuously to refill the bins. We needed a team to collect discarded sponges, which were then washed (my job) and returned for reuse as the runners passed the church four times!
There is an assignment problem here, dealing with the varied jobs that need to be done; moving water, collecting sponges, washing, handing out. Unfortunately, it is a messy problem to solve. I don't know the skills of the volunteers, and the demands on the team in fiture will depend on the weather! So, like so many messy problems, it was solved dynamically, as each of us who could transferred between tasks as required.
At the end, we had shown God's love for the community.
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