The Responsible Gambling Trust has been challenged by the Responsible Gambling Strategy Board to answer the following two questions: Is it possible to distinguish between harmful and non-harmful gaming machine play?; If so, what measures might limit harmful play without impacting those who do not exhibit harmful behaviours? Focusing on the first of these questions, this report confirms that it is possible to distinguish between harmful-and non-harmful gaming machine play. The research effort undertaken to deliver this report required the skilful processing and analysing of a large dataset using machine learning methods. By focusing on problem gambling behaviour survey data, this advanced technological approach has produced a step-change in the way gambling behaviour and specifically problem gambling behaviour is understood.