In contrast to the large body of literature on ex-ante appraisals to inform
decision-makers of estimated uncertainty levels, there is a relatively sparse
body of literature that deals with ex-post appraisals to inform decisionmakers
about observed inaccuracy levels (Van Wee, 2007). The issue is less problematic
for cost estimates than for demand forecasts, since empirical studies of
cost estimates are generally in ample supply, all of which seem to indicate a
tendency for systematic cost overruns (Siemiatycki, 2009).