Report

Phase 4: Illegal Gambling Index – Technical Report

The Gambling Commission’s technical report detailing the development of the Illegal Gambling Index.

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Published
5 November 2026

Last updated
5 November 2026 - Changes

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Contents

• Phase 4: Illegal Gambling Index – Technical Report

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• Executive summary
• Introduction
• Overview of approach
• • Timeline of the approach
  • Strengths and limitations
• Statement development
• • Statement development during Phase 1
  • Statement development during Phase 2
  • The final statements for the GSGB
• Development of the analysis approach
• • Introduction to the development of the analysis approach
  • Development of the illegal gambling index
  • Flexing the index for the GSGB
  • Recommendations for future use
• Commission modification of the index
• Final illegal gambling index
• • Final strength ratings for the index
  • Calculating the index
  • Reporting the findings
• Conclusions and next steps
• Appendices
• • Appendix A - Quota and weighting targets for representative online survey
  • Appendix B - Authorship of this report

Introduction

This report details the technical approach taken to developing statements concerning consumer usage of illegal gambling websites for the Gambling Commission’s Gambling Survey for Great Britain (GSGB). This report was produced by Yonder Consulting in collaboration with the Commission as part of their Consumer Voice Research Programme¹.

The study was designed to assess various indicators of illegal gambling website usage, to inform the Commission of key areas to focus on to track consumer engagement in the online illegal market. The research was underpinned by the Commission’s Licensing objectives as set out in the Gambling Act 2005 (opens in new tab), its Corporate Strategy, and its Evidence gaps and priorities.

The primary aim was to gain a comprehensive understanding of what behaviours and experiences can be best used to understand whether an individual has engaged with an illegal gambling website.

From a practical sense, this study had 3 output objectives:

• to develop a new set of ‘illegal gambling’ questions to be integrated into the Commission’s GSGB, accompanied by a transparent explanation of the methodology used to develop these questions
• to outline how the Commission could use these questions to track consumer engagement with illegal gambling websites over time, feeding into future monitoring and measurement of the impact of regulation
• to offer recommendations on how to repeat and update the question, and the accompanying metrics, over time, to ensure it remains relevant and reflects the contemporary consumer reality.

This report focuses on the development process for the illegal questions, as well as providing a suite of recommendations for future-proofing the question for future iterations of the GSGB.

References

¹ This report was co-authored by Yonder and the Gambling Commission. Further details on authorship of individual sections are provided in Appendix B.

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Overview of approach - Illegal gambling technical report

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Last updated: 5 November 2026

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