WebTAG: evidence review of distributional impacts

A review of the evidence base relating to distributional impact appraisals, featuring research with users of the guidance.


WebTAG: evidence review of distributional impacts

This file may not be suitable for users of assistive technology. Request an accessible format.

If you use assistive technology (such as a screen reader) and need a version of this document in a more accessible format, please email Please tell us what format you need. It will help us if you say what assistive technology you use.


This review was undertaken to ensure that distributional impact (DI) appraisal guidance remains a relevant, robust and proportionate part of transport scheme appraisal. The report includes research with users of the guidance and an update of the evidence base. This research ensures that the Department for Transport (DfT) continues to adequately take account of the distributional impacts of transport schemes in its funding decisions. This contributes to the optimal allocation of public funds.

The review makes recommendations on the evidence, usability and impact of DIs.

In terms of evidence, the review’s broad conclusion is that the guidance still reflects the state of the technical and academic literature. It makes, however, some recommendations for updating the guidance.

On usability, the review concludes that the guidance is working reasonably well with users. It includes some suggestions for making it easier to use.

In terms of impact, the review recommends that the department takes steps to reinforce the importance of DIs. It suggests that this should be done through external engagement, and raising visibility of the outputs with decision makers.

We will be using these recommendations to shape our thinking on future DI work.

Published 20 March 2015