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01 July 2026

Investability Index

The ‘Investability Index’ compares the impact of additional public investment across sectors and investment areas. 

Using the index

  1. The ‘Investability Index’ is a tool to compare the impact of additional public investment across sectors and investment areas. It scores the impacts of public investment across 24 sub-indicators, which are grouped into 4 categories: economic impact, social impact, impact on UK resilience to shocks, and deliverability. The scores are based on a wide-ranging literature review and calibrated through engagement with policymakers and economists.
  2. To interpret the scorecard, click on the row headers for a definition of the investment area and examples of investment projects; the column headers for a definition of the impacts delivered through different indicators; and the individual scores for an explanation of the key considerations informing the score.
  3. Scores of 1 – 5 indicate: 1 – Negative impact, 2 – No/minimal impact, 3 – Small positive impact, 4 – Medium positive impact, 5 – Large positive impact.


Additional resources


Acknowledgments

This scorecard and methodology has received input from a mix of policymakers and economists from across government, academia and civil society. We would particularly like to thank the following for their feedback: Tera Allas, Chris Belfield, Stefania Cerruti, Andrew Gurney, Daisy Jameson, Chris Kelly, Chaitanya Kumar, James Smith, Anna Valero, Bob Ward and Robert Woods. This list of acknowledgements should not be taken to imply that it reflects the views of those listed.


Methodological note

  1. The ‘Investibility Index’ scores how additional public investment in a variety of areas can deliver different economic impacts, social impacts, impacts on the UK economy’s resilience to shocks and how deliverable they are. 
  2. The evidence behind the scores has been gathered through a wide-ranging literature review of over 200 studies on the effect of public investment and on a variety of different returns, and calibrated through expert dialogue with policymakers in HMT and economists from academia and civil society.
  3. The investment areas encompass principal investment areas in recent HMT Spending Reviews. The analysis considers the impacts of ‘meaningful’ additional investment, beyond existing government commitments. The analysis considers investment (capital spending) and parts of day-to-day spending (resource spending) that are expected to provide a return over time. Classifications may not align exactly with those used by the UK government.
  4. The impact columns are designed to be as mutually exclusive as possible and cumulatively exhaustive – although there will inevitably be some duplication. The indicators have been weighted based on an estimate of the preferences of UK government policymakers. The scores from each indicator add up to a total score for each category (economic, social, etc). A total score has been calculated based on equal weightings of each category, minus the instances where double counting has occurred due to overlapping impacts.
  5. The score ranks investment areas, not isolated projects, but within each area there will be an array of specific projects with differing returns. The scoring considers only large projects with the highest positive impacts in each area and reflects the marginal benefit per pound in one area over another.
  6. One should not read these scores as implying that one sector matters more than another. The score points to a set of investment needs in a particular area which are likely to yield higher returns, broadly defined, than those in other areas. Users can look to particular returns they value and be guided as to which investments might generate better use of public money. It is a matter for debate where UK public spending should be targeted, and this methodology seeks to illuminate and encourage such debates, rather than provide definitive answers.