Guidance

TAGTAG: uncertainty toolkit

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

Documents

TAG: uncertainty toolkit

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Forthcoming change note to TAG uncertainty toolkit

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TAG: uncertainty toolkit, including forthcoming changes for November 2022

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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 2021.

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.

Published 19 May 2021
Last updated 218 DecemberAugust 2022 + show all updates
  1. DfT uncertainty toolkit updated.

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

  3. First published.