Objective: To ask the Leginski question of an outcome measurement process. Method: Articles elicited by a literature search of ‘HoNOS’ are analysed for evidence of its value or cost effectiveness to consumers, clinicians or administrators. Results: None of the 260 studies elicited by the search attempted to assess the cost of the use of Health of the Nation Outcome Scale (HoNOS). One study investigated the effect of routine outcome measurement, finding that it failed to result in the provision of evidence-based care. One study reported positive outcomes. Conclusions: The ability of HoNOS to improve the health and social functioning of mentally ill people has not been demonstrated. The widespread use of HoNOS as a routine outcome measure is not justified by the evidence.