Decision Theory for Planners #101 – The Paradox of Choice – ‘analysis paralysis’

Although this blog was supposed to be about decision theory I easily get distracted.

How can decision theory help us make better planning decisions?

Consider a typical local planning authority making or updating a spatial strategy, how much of housing goes to rural areas, and how much to urban, which urban areas and which directions of growth for those? A phrase I often here in consulting with such authorities is of a ‘seemingly infinate number of options’ – or words to that effect.

This is a good example of the ‘paradox of choice’ otherwise known as ‘Analysis Paralysis’.  In decision theory terms being overwhelmed by the size of the potential decision tree of potential choices.  Chess players even have a term for it – kotov syndrome.

In one ancient “fable” recorded by Aesop The Fox and the Cat, the fox boasts of “hundreds of ways of escaping” while the cat has “only one”. When they hear the hounds approaching, the cat scampers up a tree while “the fox in his confusion was caught up by the hounds.” The fable ends with the moral, “Better one safe way than a hundred on which you cannot reckon.”

A good example is the popular ‘waterfall’ model used in software development:

As Wikipedia says

‘analysis paralysis typically manifests itself through exceedingly long phases of project planning, requirements gathering, program design and data modeling, with little or no extra value created by those steps. When extended over too long a timeframe, such processes tend to emphasize the organizational (i.e., bureaucratic) aspect of the software project, while detracting from its functional (value-creating) portion.’

Imagine ‘software’ here was replaced by ‘plan making’? The big problem with the government advice post 2004 on how to deliver development plans was that it imposed this flawed and discredited waterfall model on planning when the rest of the project management world was abandoning it. A model that forces you back – often to stage 1 – each time you hit a problem. A model that forces – ‘paralysis by analysis’ gathering ever more evidence – rapidly getting out of date – to put off the dirty day of difficult but necessary decisions.

Barry Swartz in his popular 2004 Book ‘The Paradox of Choice’ argues that eliminating consumer choices can greatly reduce anxiety for shoppers.


Its like in the movie ‘Moscow on the Hudson’ where the Robin Williams character (a russian in the soviet era) has a nervous breakdown when seeing the choices available in a supermarket.

But we dont have to restrict freedoms, providing we take decisions with what is termed ‘rational ignorance‘. It is irrational to educate ourselves about something if the cost of doing so is more that the benefits of making the choice. Noone rationally spends there weekend reading the latest edition of ‘What Chewing Gum’. Its a good example for economic wonks of opportunity costs and the disutilies of labour.

The work of Gerd Gigerenzer has shown not only that making decisions on the basis of full rationality is impossible – their is never enough time or information but that instead decisions made on ‘gut feelings’, in an uncertain world, are very often better choices. He and his colleagues have shown that simple rules frequently lead to better decisions than the theoretically optimal procedure. For example his researches show that people asked in the street typically outperform stock market analysts when asked to name stocks to back – why is this?  See Gut Feelings: The Intelligence of the Unconscious (2007)

Gerds argument is that we use simple rules – what are known as hueristics – fast and frugal rules – to make these decisions. What is more we have evolved huersitics in order to interact with our environment.

To illustrate this argument in training sessions I throw a small rubber ball to a member of the audience and shot ‘catch’ then I ask them to rationally explain how they calculated where to move their hands.  We have rather evolved an inbuilt spatial awareness, an awareness to think spatially, but almost all of our education and training is training us not to think and act spatially.

Of course if the heristic is badly formed and not tested it can easily lead to extinct by instinct making a rash and  fatal decision based on hasty judgement.

Let me suggest a simple hueristic for plan making

‘Take 500-1,000 homes, allocate them directly next to your largest settlement on the road with the greatest spare road capacity and outside a flood risk area and european/nationally protected habitat’

Now this heuristic is not universally true but I would posit that 75% of authorities  will eventually include a core strategy allocation of this order, but it is precisely this 500-1,000 homes that generate the vast majority of controversy even though the eventuall allocation is inevitable – the only real question is when

Why not include public transport access in the rule – for the simple reason that outside the largest urban areas the majority of trips will be made by car, so even if a location has for example a station then the determinate issue will be spare road capacity – a good example is the arguments for growth in the Ipswich policy area, where such arguments have ruled out major development at some accessible locations.

My argument then is to start with the tough choice and work backwards, expanding a simple primary decision rule only so far as it is necessary to rule out reasonable alternatives and so far as ‘rational ignorance’ does not kick in in terms of gathering further evidence.  Such simple iterative rules are a good example of agile project decisions.

It is possible to expand this fast and frugal rule to deal with issues regarding the second largest settlement and the rural /urban split etc. etc.  Ill do this in a future post.


3 thoughts on “Decision Theory for Planners #101 – The Paradox of Choice – ‘analysis paralysis’

  1. “‘Take 500-1,000 homes, allocate them directly next to your largest settlement on the road with the greatest spare road capacity and outside a flood risk area and european/nationally protected habitat’”

    May I ask how you decided on the 500-1000 homes number?

    A similar number needs to be decided for any rural allocation. Sites may exist that are, as you say, free from flooding with transport and infrastructure capacity. To boot, they probably have deliverable developer interest, which you probably can’t guarantee for your prefered SUE right now.

    I can’t think of many situations, politically, where you’re going to go ahead and allocate the total available pool of sites, though right now that number should be as high as possible in my view. Regardless, you’re not going to escape the resulting wrangling.

    SHLAAs particularly have allowed LPAs to look at the first principle heuristics of site developability and deliverability, but the translation into DPDs doesn’t logically flow through. Maybe in some cases the inevitability should be accepted (it often is where old LP allocations and representations are rolled forward), but I feel you’re over-simplifying it a bit.

    • Two-four form entry primary school – a rational figure for a small-medium SUE – the figure is only meant to be approximate and would vary place to place.

      The only point I was making is the difficulty doesn’t lie analytically in making decisions it lies politically.

      You are right and it was a point I was going to follow up in a future post that SHLAA tell you nothing about spatial strategy, they are a filtering methodology but not a heuristic. A way of ruling out sites, not ruling them in.

      The point I think is to oversimplify what has become overcomplex.

  2. Pingback: Decision Theory for Planners #113 To decide or not to decide? – the Delay Dilemma « Decisions, Decisions, Decisions

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