Report
Phase 4: Illegal Gambling Index – Technical Report
The Gambling Commission’s technical report detailing the development of the Illegal Gambling Index.
Reporting the findings
The Gambling Commission will discuss the illegal gambling findings from the Gambling Survey for Great Britain (GSGB) using 4 respondent categories.
Those who have engaged with illegal gambling websites in the past 4 weeks
Respondents who demonstrate at least 1 ‘Near certain’ indicator or 2 ‘Strong’ indicators within the past 4 weeks. This corresponds to an index score of 18.75 when considering the past 4 weeks’ responses only.
Those who engaged with illegal gambling websites in the past 12 months
Where the above threshold isn’t met, indicators reported within the past 12 months are incorporated at a progressively lower strength rating to reflect the reduced recency of the reported behaviour. Respondents whose score then reaches the index threshold of 18.75 are assigned to this qualifying timeframe.
Those demonstrating limited indications
This includes respondents who report 1 or more indicators, but whose combination of indicator strength and recency does not reach the qualifying criteria for being categorised as an illegal gambling website user in the past 4 weeks or past 12 months. This may reflect either a score of below the 18.75 index threshold, or indicators that are historic (more than 12 months ago).
Within the GSGB, respondents were offered a ‘More than 12 months ago’ response option to ensure that those whose behaviour occurred several years earlier had an appropriate response available. However, because these responses relate to less recent activity and are more susceptible to recall error, they should be treated with caution.
Additionally, some indicators related to regulatory changes for licensed gambling websites that occurred years ago, such as the banning of credit card gambling and customers being able to cancelling the withdrawals. These changes were introduced in 2020 and 2021 respectively, so some respondents may report engaging in these behaviours prior to the bans occurring. For example, a respondent who recalls using a credit card on a gambling website 10 years ago may select ‘More than 12 months ago’, but this behaviour would not necessarily indicate illegal gambling website use as it occurred before this capability was banned on licensed gambling websites.
Some respondents in this category may achieve the 18.75 index score threshold, even after accounting for the reduced weighting and timeframe of the indicators they reported. However, where all relevant indicators relate solely to behaviours that occurred more than 12 months ago, these respondents remain classified within this category and are not considered illegal gambling website users
Important: Note that although the Commission will publish findings relating to those demonstrating limited indications of engagement with illegal gambling websites, this is primarily for completeness of reporting. Interpretation and discussion should focus on respondents who meet the threshold for likely illegal gambling website use, rather than those in the limited indications category.
No indications
Respondents with a score of 0 who demonstrate no indication of engaging with illegal gambling websites.
Calculating the index
Last updated: 5 November 2026
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