Guidance

TAG uncertainty toolkit

Toolkit for analysing and presenting information on future uncertainty in the transport system.

Documents

TAG uncertainty toolkit

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Details

A toolkit that provides practical information on:

  • the analysis of uncertainty in modelling and appraisal
  • techniques for exploring that uncertainty in the context of future travel demand
  • how to present this data to decision-makers
  • the common analytical scenarios, including narratives and how to apply them proportionately in transport business cases

It supplements TAG Unit M4: forecasting and uncertainty.

A common analytical scenarios databook has also been published.

The previous version of this guidance was released in May 2023.

TAG provides information on the role of transport modelling and appraisal, and how the transport appraisal process supports the development of investment decisions to support a business case.

Updates to this page

Published 19 May 2021
Last updated 30 November 2023 + show all updates
  1. TAG uncertainty toolkit updated.

  2. Added forthcoming change about appraisal guidance updates.

  3. TAG uncertainty toolkit updated.

  4. Added forthcoming change: spring 2023 data book and guidance updates.

  5. DfT uncertainty toolkit updated.

  6. Forthcoming change to guidance note added, giving details of updates to be made in November 2022.

  7. First published.

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