3.3 Building the business case:
Robust and consistent evidence

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The DfT provides specific guidance for the development of Transport Business Cases through its Web-based Transport Appraisal Guidance (WebTAG). WebTAG provides advice on how to set objectives and identify issues, to develop options and test the pros and cos of each using appropriate modelling and appraisal tools. The guidance is structured to be accessible to both decision-makers and analysts.

WebTAG goes some way towards providing a common analytical framework so that competing investment options can be appraised on a like-for like basis. The framework also strengthens the transparency and accountability in decision-making.

The type of analysis required to inform investment decisions is complex and needs to be supported by proportionate analytical assurance processes that provide comfort to analysts and decision-makers that the insight provided can be relied on. The DfT’s Analytical Assurance Framework (Strength in Numbers) covers: analytical roles and responsibilities, analytical strategies (governance and approvals) and the management of business critical analytical models. The Framework aims to convey to decision-makers the strengths, risks and limitations in the way that the analysis has been conducted and the uncertainty in the analytical advice.

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Key takeaways

The DfT has well-defined processes to assess Transport Business Cases, supported by detailed methodologies to ensure consistent, evidence-based decision-making.

To meet new goals and targets, local decision-makers need to balance competing factors including: strategic objectives, economic benefits, financial affordability, asset scale and condition, and customer expectations taking account of internal resources and capabilities.

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3.4 Funding and financing of transport infrastructure and services