Why we need an internationally shared rehabilitation definition for clinical research purposes
Purpose: Responding to a recent editorial arguing against defining rehabilitation, we discuss the reasons for developing a classification of rehabilitation for research purposes, its philosophical background and some of the possible risks. Why define: Science requires the definition and classification of phenomena to allow replication of experiments and studies, and to allow interpretation and use of the findings. As understanding increases, the definitions can be refined. Defining rehabilitation does run the risk of excluding some interventions or practices that are either considered rehabilitation (perhaps wrongly) or are rehabilitation interventions; when identified, these errors in definition can be remedied. Defining rehabilitation for research purposes should not inhibit but could (possibly) orient research. Risk of not: Without a definition, rehabilitation will remain in a permanent limbo. Experts will (apparently) know what it is, while others are left guessing or failing to comprehend or recognise it. This uncertainty may reassure some people, because all possible interventions are included; we argue that it downgrades the understanding of our field because interventions that are not rehabilitation are, nonetheless, called rehabilitation. In an era of international collaboration, and of undertaking systematic reviews with metanalysis, we need a shared definition. Conclusion: Terminology is often controversial, but definition enables progress in understanding such that terms themselves can evolve over time.