Clinical Trial

Introduction: Clinical trials are a common type of medical research that has grown in number over the past decade. Intervention studies or trials are the most authoritative type of epidemiological studies and provide the strongest evidence of causation and effect relationships between phenomena. Despite the usefulness of many of these studies, potential bias can distort the results of the study. Therefore, in this study, we investigated a summary of the types of clinical trials studies, design and possible biases.