Purpose of review: The purpose is to review the arguments for increasing use of existing data in health research.
Recent findings: The reuse of data in observational, exploratory and outcome studies, as well as in confirming other findings, is being justified on epistemological grounds as the major path to new knowledge and to the generalizing of findings to ‘real world’ populations. It is also justified on the grounds of cost, power, and efficiency, even though data reuse comes with real informatics, scientific culture, societal, and regulatory issues.
Summary: Data reuse is becoming more compelling. When contemplating new research for any purpose other than RCTs for efficacy, it is prudent to consider whether partnership with existing data holders should be part of the optimal research plan.