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Research Summary

How common is problem gambling? What the global research shows

Citation

Calado, F., & Griffiths, M. D. (2016). Problem gambling worldwide: An update and systematic review of empirical research (2000–2015). Journal of Behavioral Addictions, 5(4), 592–613. View source ↗

Study overview

This systematic review pulled together adult general-population gambling surveys published between 2000 and 2015 across dozens of countries, comparing how researchers measured problem gambling and what prevalence rates they found.

Methodology summary

The authors searched academic databases for population-representative surveys (not clinical or treatment-seeking samples) that used validated screening tools such as the SOGS or PGSI. Because studies used different screening instruments, sample ages, and time frames (lifetime vs. past-year), the review reports a range of estimates rather than a single global number.

Key findings

Limitations

Cross-study comparison is genuinely difficult: surveys use different screening thresholds, time windows, and sampling methods, so a rate reported in one country isn't directly comparable to another without accounting for methodology. Self-report surveys are also subject to under- or over-reporting, and response rates in some national surveys were modest, which can bias results in either direction.

Practical meaning

There is no single, universally agreed prevalence figure — the honest answer is a range, not a number. What's consistent across studies is that severe, clinically-defined gambling disorder is uncommon (well under 2% of adults in most surveys), while broader 'at-risk' categories are meaningfully more common. This is part of why WillHills treats responsible-gambling tools as something every player benefits from having available, not just a minority.

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