Three risk of bias tools lead to opposite conclusions in observational research synthesis

Assessing RoB using the three tools may lead to opposite conclusions, especially at low and high levels of RoB. Domain-based tools (Q-Coh and ROBINS-I) provide a more comprehensive framework for identifying potential sources of bias, which is essential to improving the quality of future research. Both further guidance on the application of RoB tools and improvements in the reporting of primary studies are necessary.