Should small schools be closed? Is the government right to build giant prisons? These two questions share a common theme - the theme being that the government's pretensions to technocratic expertise are a sham.
In principle, the question of what size schools or prisons should be is a narrow technical - mere mathematical - one. The question is simply: what is the production function?
Take prisons. A desirable output might be a low recidivism rate. Our independent variables might include prison size, guard-prisoner ratio, money spent on therapies and education, diet, controls for the type of prisoner and so on. We then regress the recidivism rate upon these variables across all prisons, and estimate the coefficients. We can then see the impact prison size has upon recidivism.
Prison size, then, is not a political question, but a mathematical one.
So, why are questions of school or prison size political ones, rather than mere maths? Here are some possibilities:
1. There are multiple desirable products of schools or prisons. For example, in schooling the desire to maintain community cohesion might argue for small schools, whilst exam grades might argue for larger ones. The production function approach still has a role here, however, as it allows us to better estimate the trade-offs between these objectives. It allows us to say (for example): "keeping a village school open costs one GCSE per student."
2. The notion of a production function might be incoherent. There might be more than one optimum technique. For example, big prisons might work well with big spending on education, but worse than small prisons if there's little such spending.
3. There might be insufficient variation in inputs to allow us to estimate coefficients well - for example, if spending per pupil varies little from school to school.
4. Politicians - and unions - might not like what production functions say. For example, there's evidence (pdf) that spending on schools on its own doesn't (pdf) do much to improve outcomes.
5. Drawing attention to production functions forces politicians to look at outputs, not inputs. Their boasts of spending billions more on education (or health) become vacuous. And they have to do the grunt work of actually making things work.
Whatever the reason, the fact's the same. In not thinking about the maths of production functions, politicians - unless they have Sraffian doubts about their efficiacy, which I doubt - are like cargo cults. They practice a sham ritualistic imitiation of rational management, not the substance of it.