A great blog from Cliff Hague on his first planning job 50 years ago – and time to have some fun with it.
My report on the Queen’s Dock was not in the mode that Glasgow Corporation planning Department had previously encountered. I analysed two alternatives for the site, an exhibition centre or using it to build council housing and associated play facilities. They were evaluated using Morris Hill’s Goals Achievement Matrix, based on the paper he had oublished in the Journal of the Ameican Institute of Planners in January 1968. Unfortunately, the analysis revealed that in terms of a rational planning choice, thre was not much to choose between the two alternative futures: much ado about nothing. Perhaps I was more cut out for an academic career.
There is a flaw in the standard goals achievement matrix – it assumes both alternatives are perfect substitutes for each other and there is no opportunity cost.
Let me explain. Lets say it was housing v employment, with a large number of alternative sites for both. Then there is little opportunity cost. But for a use like an exhibition centre there might be very few.
So the benefits of each use need to be set off against the probability of blocking a possible site for the alternative use, multiplied by the benefits of the alternative use – the opportunity cost. Planning is about hard trade offs.
So that exhibition site might have had only 2 or three alternative sites – with a high probability that the difficulty of finding a site would cause delay – which we know because it took another 35 years. So the exhibition centre should have won hands down.
The GAM method is about comparing plans, you get into big problems using it to compare alternative uses for the same site. In any place where land is scarce there will always be uses that fall off the plan and which need accounting for in the appraisal. This is not an academic question. we use variants of GAM every day when we IIA or SEA plans.
I had a lecturer (not Cliff) who amusingly claimed he used GAM to assesses problems in his personal life – he would have been happy had he used it to assess leaving his wife.