Influence of reference points in ex post evaluations of rail infrastructure projects

Nils O.E. Olsson
Hans Petter Krane
Asbjørn Rolstadås
Mads Veiseth

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The paper study the effect of different reference points in time regarding the ‘before’ and ‘after’ situation and how this may influence the ex post evaluation. Four Norwegian railway projects are analysed ex post. We have found that the choice of reference points that are chosen to represent the situation before and after a project, respectively, will often have a major impact on the result of an evaluation. In fact, the studied projects can be presented as either successes or failures, depending on the choice of reference years. The parameters used in this comparison are punctuality, frequency, travel time, and number of travellers. Four projects have been studied. Four parameters for each project generate a total of 16 indicators. By selecting certain years as reference years, 11 of the 16 indicators can be presented as either an increase or decrease. Stakeholders with a biased agenda towards certain projects can actually pick reference years to present the outcome of projects in a way that that fit their agenda. It is recommended that more than one measurement approach is applied in ex post evaluations.