Thursday, 3 April 2014

Queues and inventory, over and over again

The tag-line "The Science of Better" has been applied to operational research for several years.  I was once asked in a large lecture what was the most important ability in a potential O.R. scientist;  I think that the questioner expected me to say something about mathematical skills.  But my answer was not about academic skills.  I suggested that the ability which was most desirable was the potential to look at some everyday system, identify if it was efficient, and if not, suggest how one would make it more efficient - in other words, a triple skill of "look, think, and make it better".

One of my academic colleagues was often asked why students needed to be taught the economic order quantity formula in inventory control.  Surely, the questioners said, the formula has been around for long enough for it to have entered into use in every situation where it might be used?  My colleague generalised the question, and suggested that we needed to teach the basic methods of O.R. over and over again, because those basic methods had not been adopted everywhere.  He went on to say that many practitioners of O.R were being called on to solve the same problems that O.R. practitioners of a generation ago.  The context may be different, but the O.R. practitioner with that "look, think, and make it better" attitude will recognise the problem, use her expertise and tackle the problem (providing they have the remit to do so).

Progress in O.R. has brought in more ways of thinking about making systems better, ways of thinking about making more systems better, more tools of different kinds to use, but that triple skill remains constant.

Why was I thinking about this?  Here I have to be very tactful.  I have mentioned before that my "dinner table" explanation of what O.R. people do is to ask about the number of cashiers who should be at the tills in a supermarket.  Last week I went through this modelling scenario with a friend.  He listened with interest (I think), thought - and asked whether I knew his local supermarket, since the shop clearly did not have a very good model for staffing checkout tills.  I laughed, and said that I knew the store, and also that another of O.R.'s tools was not being used, since the stock control of fruit and vegetables was very inefficient.  For the last five or six summers, I told him, Tina and I have gone there and stocked up with cheap strawberries, reduced in price because the store had seriously over-stocked every year, and we made strawberry jam.and enjoyed strawberry teas with the best of the fruit.  I commented that another branch of the same chain in Exeter had exactly the same problems of cashier numbers and stock control. 

Later, I tried to recall whether I had ever heard of anyone employed to do O.R. for that supermarket chain, and couldn't.  There may be someone, but if so, they keep a very low profile in the U.K. practitioner community.  Then I did a search using the terms "operational research" and "???? food" where ???? is the name of the chain, which I do not want to mention by name.  And I had really good hit; a discussion about a recent reshuffle of the management of the supermarket chain, followed by the comment:
"The big boys have been far too long at the top. I am fairly certain, ..., you have totally lost it with respect to supply chain management, and my favourite, operational research and logistics. Probably even more important as consumers have already reached disposable income saturation, that the word socio-economics is out of your remit" 

The suggestion was that nobody at the top level had responsibility for making the whole system work better; the priority was to maintain an image, an ideal, without striving for efficiency.  

But, unless the company recognised its need for employing someone with those triple skills, customers with those skills will continue to be frustrated - and probably shop elsewhere (until they want cheap strawberries).