Pragmatic clinical trials (PCTs) often study interventions delivered within the context of standard clinical encounters with the overall goal of producing generalisable knowledge to inform implementation strategies and health policy.1 In reality, however, PCTs have a gradient of pragmatic and explanatory features, as described by the PRagmatic Explanatory Continuum Indicator Summary, 2nd edition (PRECIS-2) framework.2 To facilitate the process of iterative learning, PCTs and comparative effectiveness trials frequently test interventions shown to be effective in explanatory trials, the latter having more stringent entry criteria. PCTs are particularly valuable for assessing use of non-pharmacological interventions, such as those designed to manage pain. Conducted in settings involving a broad range of patients and delivered by a range of qualified clinicians that may or may not have a research background, PCTs can illuminate implementation barriers and practice variations affecting the delivery of clinical interventions that may or may not be widely supported by institutional culture.

Terminology is essential to determine study risk appropriately and to interpret trial results accurately. Ambiguity in the use of terms used to describe (and differentiate) control and experimental interventions surfaces in unexpected ways, driven by context-specific notions of efficacy and trial oversight. Inconsistent use (and thus variable interpretation) of the terms usual care, standard of care, validated care and experimental care by researchers, institutional review boards, clinical staff and patients can create confusion that affects the conduct of PCTs. In particular, capricious use of the term ‘usual care’ used in PCTs challenges the manner in which ethics and regulatory determinations are made. Without a clear understanding of the use of care terminology, the full practical potential of PCTs can be compromised, potentially affecting the scientific integrity of important clinical research activities and limiting the studies’ value. Within PCTs, evaluating non-pharmacological pain management interventions, clinical staff may …