ClinicalTrials.gov

"ClinicalTrials.gov is a registry and results database of federally and privately supported clinical trials conducted in the United States and around the world. ClinicalTrials.gov gives you information about a trial's purpose, who may participate, locations, and phone numbers for more details. This information should be used in conjunction with advice from health care professionals."

Analyses of data at ClinicalTrials.gov gives insights into methods and execution of randomized controlled trials. An example is an analysis of publication bias.