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...

Based on a review of available data from a database on large‐scale transport infrastructure projects, this paper investigates the hypothesis that traffic forecasts for road links in Europe are geographically biased with underestimated traffic volumes in metropolitan areas and overestimated...

A major source of risk in project management is inaccurate forecasts of project costs, demand, and other impacts. The paper presents a promising new approach to mitigating such risk based on theories of decision-making under uncertainty, which won the 2002 Nobel Prize in economics. First, the...

This article examines five common misunderstandings about case-study research: (a) theoretical knowledge is more valuable than practical knowledge; (b) one cannot generalize from a single case, therefore, the single-case study cannot contribute to scientific development; (c) the case study is...

This paper presents results from the first statistically significant study of traffic forecasts in transportation infrastructure projects. The sample used is the largest of its kind, covering 210 projects in 14 nations worth US$58 billion. The study shows with very high statistical significance...

The Summer 2005 issue of JAPA contains a letter from the President of the American Public Transportation Association, William Millar, regarding our article “How (In)accurate Are Demand Forecasts in Public Works Projects? The Case of Transportation,” printed in the Spring issue. We concluded...

Project promoters, forecasters, and managers sometimes object to two things in measuring inaccuracy in travel demand forecasting: (1) using the forecast made at the time of making the decision to build as the basis for measuring inaccuracy and (2) using traffic during the first year of...

This article presents results from the first statistically significant study of traffic forecasts in transportation infrastructure projects. The sample used is the largest of its kind, covering 210 projects in 14 nations worth U.S.$59 billion. The study shows with very high statistical...

Some argue that almost no projects, including our most treasured ones, would ever be undertaken if some form of deception about costs and benefits weren‘t involved. The Brooklyn Bridge, for instance, had a cost overrun of 100%, the Sydney Opera House of 1,400%. Had the true costs been known,...

Some years ago I was threatened by a high-ranking government official as I was beginning research on cost overrun in large public works projects. The official told me in no uncertain terms that if I came up with results that reflected badly on his government and its projects he would personally...