Improving Transport Project Appraisals
In the Islamic Countries
45
million, or €23.6 million (Statens vegvesen, 2006) The stated goal is to check the accuracy of the
information included in the ex-ante CBA and to analyse the reasons for any deviations between
and ex-ante and ex-post results. To this end, the same methodologies used ex-ante are adopted
in the new assessment as well.
Beyond the focus on comparing new figures with the ones forecasted in the ex-ante appraisal in
order to detect errors and deviations, ex-post evaluation aims to investigate the mid- or long-
term contribution of completed projects. An ex-post evaluation increases the accountability of the
decision-making and implementation processes , by giving evidence to the investment
effectiveness in relation to the initial goals. In addition, it can constitute a significant learning
mechanism. Retrospective analysis may indeed feed into ex-ante appraisal of future projects, for
instance by limiting optimism bias thanks to an improved collection of project benchmarks and
through an assessment of the conditions under which projects actually delivered expected long-
term effects (Florio, 2014).
As far as ex-post evaluation is concerned, the following trade-offs shall be addressed: whether
obligations exist to carry out ex-post evaluation, or if it is left to occasional initiatives; whether
rules exist on how many years after project completion it should be carried out, or if it is left to
a discretionary choice of single procurement agencies; whether it is carried out on a highly
selective basis or rather periodically on a sample of investments, or even systematically on all
major investments; whether it is conducted internally by the public sector or outsourced. More
generally, the existence of a system to report frequently encountered drawbacks should be
examined.