How optimism bias and strategic misrepresentation in early project development undermine implementation

Flyvbjerg, Bent (2007) How optimism bias and strategic misrepresentation in early project development undermine implementation. In: Sunnevåg, Kjell J., (ed.) Beslutninger på svakt informasjonsgrunnlag: tilnærminger og utfordringer i prosjekters tidlige fase [Decisions Based on Weak Information: Approaches and Challenges in the Early Phase of Projects]. Concept Rapport (17). Concept-programmet, Trondheim, pp. 41-55. ISBN 978-82-92506-50-9

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The American Planning Association recently endorsed a new forecasting method called reference class forecasting, which is based on theories of planning and decision-making that won the 2002 Nobel prize in economics. This paper details the method and describes the first instance of reference class forecasting in planning practice. First, the paper documents that inaccurate projections of costs, demand, and other impacts of plans are a major problem in planning. Second, the paper explains inaccuracy in terms of optimism bias and strategic misrepresentation. Third, the theoretical basis is presented for reference class forecasting, which achieves accuracy in projections by basing them on actual performance in a reference class of comparable actions and thereby bypassing both optimism bias and strategic misrepresentation. Fourth, the paper presents the first case of practical reference class forecasting, which concerns cost projections for planning of large transportation infrastructure investments in the UK, including the Edinburgh Tram and London's £15 billion Crossrail project. Finally, potentials for and barriers to reference class forecasting are assessed.

Item Type: Book Section
Keywords: Major projects; decision making; optimism bias; strategic misrepresentation
Subject(s): Project management
Centre: BT Centre for Major Programme Management
Date Deposited: 16 Jun 2011 15:08
Last Modified: 23 Oct 2015 14:05

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