Evidence-based practice: What evidence is missing?

Background: Evidence-based practice (EBP) is defined as "an approach in which current, high-quality research evidence is integrated with practitioner expertise and client preferences and values into the process of making clinical decisions" (ASHA, 2005). Evidence-based practice has gained significant momentum around the world. Many professional healthcare organisations, including those associated with speech-language pathology, have recommended that clinicians incorporate EBP into everyday clinical practice. Aims: An approach such as EBP relies on the practitioner being able to locate high-quality research in order to provide data that informs his/her clinical decision making. The present paper lists at least five possible sources of bias that serve to reduce available evidence within EPB: funding bias, publication bias, consumer/researcher mismatch, reduced clinical applicability, and over-reliance on randomised controlled trials. Main Contribution: Possible sources of bias within the EPB process, resulting in "missing" evidence are outlined and illustrated. Specific examples are provided from various healthcare fields. Conclusions: It is suggested that discussion of sources of bias within EBP may help to maximise its potential. Audience suggestions provided at the 2005 Clinical Aphasiology Conference regarding possible directions for future work in this are appended.