The use of data from observational studies has a long tradition in epidemiological research. A series of complex study designs and analysis procedures, such as propensity score methods, have been ...

Data regarding the effect of radiotherapy on mortality in patients with breast cancer diverged widely between randomized clinical trials and observational data, even after adjustment for potential ...

Comparative effectiveness research increasingly is being recognized as a priority area in cancer research. Although researchers have been conducting comparative effectiveness research for decades, ...

Observational studies using population-based registry data are increasingly relied on to fill the information gaps created by lack of evidence from randomized controlled trials. Administrative data ...

Correlations tell you that ... Untangling such knotty questions is typically done via rigorous observational studies or randomized ... If one data set shows a correlation between ...

Although observational studies have inherent limitations, they provide valuable information that should not be dismissed in favor of only using data from randomized studies. Box 1 Definitions of ...

Big data has irreversibly changed medical research. There is an increasing body of literature in selected settings demonstrating RCTs can be supplemented by or substituted with observational studies.