In the hierarchy of research designs, randomised controlled trials and metaanalyses of randomised controlled trials are considered to be the highest level of evidence. They have been established as essential areas of research since their introduction into clinical sciences. Research in the interventional disciplines such as surgery, rely mostly on observational studies. Therefore, the quality and quantity of randomised trials with regards to interventions remain limited. Researchers in these

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... ciplines face various obstacles during building, assessment or implementation of evidence. This chapter aims to provide a critical overview of the obstacles to randomised trials and meta-analyses. It also proposes solution to these problems.