Sources of bias in clinical trials: Cochrane Handbook Part II General methods for Cochrane reviews, Section 8 “Assessing Risk of bias in included studies”, Introduction to sources of bias in clinical trials
AHRQ ’12 Assessing the Risk of Bias of Individual Studies in Systematic Reviews of Health Care Interventions, Appendix A
ROBIN-I (Risk of Bias in Non-randomized studies of Interventions) tool
Below are tools and articles about tools for assessing quality of research. We recommend you investigate what tools have been used in other reviews on your subject/in your discipline.
Jadad tool for assessing quality