This study examined if a macro-, meso-, and micro outcome measurement instrument that constitutes the evaluation stage of a Dutch forensic psychiatric outcome monitor, the Hoeven Outcome Monitor (HOM), can provide a first step towards a more evidence based groundwork in forensic mental health. General, serious, very serious, special, and tbs meriting recidivism during treatment, after treatment, and overall were charted for forensic psychiatric patients discharged from a Dutch forensic psychiatric centre between 1999 and 2008 (N = 164). Re-conviction data were obtained from the official Criminal Records System, and the mean follow-up time was 116.2 months. First, the results showed that the macro-measurements provide comparative outcome measures to generate insight into the overall effectiveness of forensic psychiatric treatment. Second, the meso-measurements yielded clinically relevant treatment outcome data for all discharged patients to generate a complete view of treatment effectiveness. Finally, the micro-measurements allowed access to detailed patient and treatment effectiveness assessments that provides the empirical foundation to conduct aetiological research into the prediction and control of high-risk behaviour. Thus, an outcome measurement instrument in line with Evidence Based Medicine and best practice guidelines was designed that provides an empirically sound evaluation framework for treatment effectiveness, and an impetus for the development of effective interventions to generate an evidence based groundwork in forensic mental health.