The University of Amsterdam research was led by PhD candidate Charles de Leau in collaboration with psychology professor Reinout Wiers and computer science professor Johan Bollen. ZonMw financed the project through the KSA’s Addiction Prevention Fund.
The project reflects the KSA’s wider investment in evidence-based gambling harm prevention, including initiatives focused on earlier risk detection, intervention and support.
The researchers obtained betting data covering every player at 13 Dutch online casinos from 30 July 2023 to 30 July 2025. They accessed the information through a provision in Dutch law requiring casinos to make user data available for independent research.
De Leau was the first—and, at the time of publication, the only—researcher to use this statutory provision. According to the University of Amsterdam, an independent analysis of every bet made across 13 casinos over two years had not previously been conducted on this scale.
The model assesses several aspects of actual gambling behaviour:
- How much and how frequently a player wagers;
- When gambling sessions take place, including repeated night-time activity;
- Whether a player continues gambling across consecutive days;
- How behaviour changes during winning and losing streaks.
The model uses these patterns to generate a risk score. All forms of online gambling were included in its development.
The resulting score highlights behaviour that may require further investigation. It does not provide a clinical diagnosis or, by itself, confirm that a player is experiencing gambling-related harm.