Many different themes dominate the current literature on mental health services. Services should facilitate meaningful outcomes. The mission should be recovery. Interventions should be evidence based. Care should be client centred or self-directed. The mental health system should diminish stigma and foster social inclusion. Information technology should enhance efficiency. And many more! Each of these represents an endangered species. Why endangered? Simply put, philosophical movements easily become transient fads when they are not grounded in measures, numbers and data. Ideas, goals, guidelines, missions, benchmarks and plans require measurement to attain any hope of enduring reality. If nothing is measured, nothing changes. Instead, the next year brings a new commitment to yet another banner idea.

Mental health has long suffered from lack of measurement – a tradition extending back to the days when lack of measurement was valorised by clinicians who argued that the entire enterprise was too personal, ethereal or mystical to measure. Mental healthcare has, though, emerged from the dark ages. Although we still lack clear biological and physiological standards, measurement must be at the core of what we do. And measurement is no simple matter.

As the authors of the following chapters argue, measurement in mental health is serious and arduous work. We need measures that are reliable and valid, that address meaningful processes and outcomes, that uphold and reinforce our values, and that enhance rather than impede the enterprise of behavioural health. Developing, refining, testing, comparing and instantiating such measures are essential tasks if the field is to move forwards, rather than recycle old ideas in new terminology.

I commend the editors for their persistent efforts to encourage high-quality research. The chapters herein describe progress on many important fronts.