Performance, Detection, Contamination, Compliance, and Cointervention Biases in Rehabilitation Research: What Are They and How Can They Affect the Results of Randomized Controlled Trials? Basic Information for Junior Researchers and Clinicians

Bias is a systematic error that can cause distorted results leading to incorrect conclusions. Intervention bias (i.e., contamination bias, cointervention bias, compliance bias, and performance bias) and detection bias are the most common biases in rehabilitation research. A better understanding of these biases is essential at all stages of research to enhance the quality of evidence in rehabilitation trials. Therefore, this narrative review aims to provide insights to the readers, clinicians, and researchers about contamination, cointervention, compliance, performance, and detection biases and ways of recognizing and mitigating them. The literature selected for this review was obtained mainly by compiling the information from several reviews looking at biases in rehabilitation. In addition, separate searches by biases and looking at reference lists of selected studies as well as using Scopus forward citation for relevant references were used.This review provides several strategies to guard against the impact of bias on study results. Clinicians, researchers, and other stakeholders are encouraged to apply these recommendations when designing and conducting rehabilitation trials.