ABSTRACT
Researchers and readers of research need to know about bias. Bias affects the validity and scientific quality of a study and, in turn, the robustness of the evidence to guide clinical practice. As is apparent throughout this volume of 44 chapters, and from the 755 systematic reviews archived on the specialty evidence data-base, PsycBITE, 1 the quantum of evidence on neuropsychological interventions for people with acquired brain impairment is enormous. The consumer (whether clinician, researcher, patient, family member, student, educator or policy maker) is faced with a colossal task, not only keeping up to date with such a volume of work, but also ensuring that the scientific quality of the work being accessed is sound. So the question is, does the peer review process conducted by scientific journals actually ensure that only high quality research free from bias is published? Or is it a case of ‘some (perhaps most) published articles belong in the bin, and should certainly not be used to inform practice’ (Greenhalgh, 1997, p. 243)?
