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1. Introduction
There are a considerable number of projects where time is a great concern, even more important than other project management subject groups, provided that cost, scope and quality are not extensively compromised. Furthermore, even if a project is not mainly time-constrained, completing projects on time is generally an indicator of an efficient industry (Chan and Kumaraswamy, 1997). Flyvbjerg (2008, p. 5) reports that 20-45 per cent of projects do not meet their original time and cost baseline, and that this has not changed for the last 70 years (Flyvbjerg, 2006, p. 7). During this time extensive “improvements” have been made to project controls and methods, including critical path method, program evaluation and review technique (PERT) and work breakdown structure, yet project performance has improved little from both a schedule and cost perspective.
Numerous papers (Flyvbjerg, 2006; MacDonald, 2002; Morris and Hough, 1987) have also shown that the original baseline was not a good predictor of how long the project would take, and that the basis of poor project performance was often not project execution but under-estimation of baselines (Eizakshiri et al., 2015). One significant cause of this under-estimation has been shown by research to be optimism bias, a human behavioural characteristic first identified by Kahneman and Tversky in 1977. Flyvbjerg (2006, p. 6) defined it as “a cognitive predisposition found with most people to judge future events in a more positive light than is warranted by actual experience”. Broadly, it means that people, when asked to forecast the future, do not consider history or unforeseen events. Thus, the relatively new technique of capturing and reviewing lessons learnt to learn from previous projects may be biased as well.
Optimism bias is a process of our brain that guides judgement (Shepperd et al., 2002, p. 65) and can be described as the way we actually think, not the way we think we think. The perception is that the way we think is logical and rational where in fact it is quite contrary to that. Shepperd et al. (2002, p. 77) summarise this very well, commenting that “our review reveals that there are a multiple motivational, cognitive and affective accounts for why people overwhelming prophesize that their future will be better than the...