Bent Flyvbjerg
Professor, Research Director, Dr. Techn., Dr. Scient., and Ph.D.
When Planners Lie with Numbers
The text below is an excerpt from the article "How (In)accurate Are Demand Forecasts in Public Works Projects? The Case of Transportation," by Bent Flyvbjerg, Mette Skamris Holm, and Søren Buhl, published in Journal of the American Planning Association, vol. 71, no. 2, Spring 2005. For notes and references, please see the article.
In the present section we consider the situation where planners and other influential actors do not find it important to get forecasts right and where planners, therefore, do not help to clarify and mitigate risk but, instead, generate and exacerbate it. Here planners are part of the problem, not the solution. This situation may need some explication, because it possibly sounds to many like an unlikely state of affairs. After all, it may be agreed that planners ought to be interested in being accurate and unbiased in forecasting. It is even stated as an explicit requirement in the AICP (American Institute of Certified Planners) Code of Ethics and Professional Conduct that "A planner must strive to provide full, clear and accurate information on planning issues to citizens and governmental decision-makers" (American Planning Association 1991, A.3), and we certainly agree with the Code. The British RTPI has laid down similar obligations for its members (Royal Town Planning Institute 2001).
However, the literature is replete with things planners and planning "must" strive to do, but which they don't. Planning must be open and communicative, but often it is closed. Planning must be participatory and democratic, but often it is an instrument to dominate and control. Planning must be about rationality, but often it is about power (Flyvbjerg 1998, Watson 2003). This is the "dark side" of planning and planners identified by Flyvbjerg (1996) and Yiftachel (1998), which is remarkably underexplored by planning researchers and theorists.
Forecasting, too, has its dark side. It is here "planners lie with numbers," as Wachs (1989) has aptly put it. Planners on the dark side are busy, not with getting forecasts right and following the AICP Code of Ethics, but with getting projects funded and built. And accurate forecasts are often not an effective means for achieving this objective. Indeed, accurate forecasts may be counterproductive, whereas biased forecasts may be effective in competing for funds and securing the go-ahead for construction. "The most effective planner," says Wachs (1989, 477), "is sometimes the one who can cloak advocacy in the guise of scientific or technical rationality." Such advocacy would stand in direct opposition to AICP's ruling that "the planner's primary obligation [is] to the public interest" (American Planning Association 1991, B.2). Nevertheless, seemingly rational forecasts that underestimate costs and overestimate benefits have long been an established formula for project approval (Flyvbjerg, Bruzelius, and Rothengatter 2003). Forecasting is here mainly another kind of rent-seeking behavior, resulting in a make-believe world of misrepresentation which makes it extremely difficult to decide which projects deserve undertaking and which do not. The consequence is, as even one of the industry's own organs, the Oxford-based Major Projects Association, acknowledges, that too many projects proceed that should not. We would like to add that many projects don't proceed that probably should, had they not lost out to projects with "better" misrepresentation (Flyvbjerg, Holm, and Buhl 2002).
In this situation, the question is not so much what planners can do to reduce inaccuracy and risk in forecasting, but what others can do to impose on planners the checks and balances that would give planners the incentive to stop producing biased forecasts and begin to work according to their Code of Ethics. The challenge is to change the power relations, which governs forecasting and project development. Here better forecasting techniques and appeals to ethics won't do; institutional change with a focus on transparency and accountability is necessary.
Two basic types of accountability define liberal democracies: (1) Public sector accountability through transparency and public control, and (2) Private sector accountability via competition and market control. Both types of accountability may be effective tools to curb planners' misrepresentation in forecasting and to promote a culture which acknowledges and deals effectively with risk. In order to achieve accountability through transparency and public control, the following would be required as practices embedded in the relevant institutions: [...continues at length...]