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Peer review of First Interim Evaluation of High Speed 1

The Department for Transport (DfT) commissioned Oxera Partner, Andrew Meaney [1], to carry out a peer review of the First Interim Evaluation of High Speed 1 (HS1) report prepared by Atkins, AECOM and Frontier Economics  [2]. The scope of his review focused on the approach and methodology described in the report and Appendices. It did not include a detailed audit of the models or other spreadsheets underlying the report.

In summary, the First Interim Evaluation of High Speed 1 (HS1) report presents a useful initial analysis of the impact of HS1, and the estimation of the impacts and benefits of the project broadly follows established methodologies such as WebTAG and the Passenger Demand Forecasting Handbook. That said, I consider that there could have been scope to explore whether the assessment could have been extended to take into account the large, and potentially transformational, nature of HS1.

The use of a survey to establish a counterfactual case has clear limitations, and highlights the importance of establishing a monitoring and evaluation plan in the early stages of scheme development. While the report’s authors do note the issues associated with relying on the survey, Andrew Meaney considers that there could be greater use of supplementary evidence as a cross-check. More reference could also be made to the original ex ante appraisal to provide useful context for the reader.

Finally, Andrew Meaney notes that the use of the demand cap in the forecast is likely to understate the benefits of the project and potentially overstate the costs. While the approach is in line with current appraisal guidance, it is less appropriate for assessing a completed project.

[1] The views expressed in this document are those of the author (Andrew Meaney) alone, and represent his professional opinions on the matters to which they refer.

[2] Atkins, AECOM, Frontier Economics, ‘First Interim Evaluation of the Impacts of High Speed 1: Final Report: Volume 1 – Main Report’.