Insufficient Evidence (I) Statements of the U.S. Preventive Services Task Force: A Rich Information Resource for Prevention Researchers

Introduction: Evidence-based recommendations about clinical preventive services can improve the health of all Americans. Research gaps in key areas of knowledge inhibit the development of such recommendations, limiting the potential benefits of population-based disease prevention.

The NIH Office of Disease Prevention is disseminating research needs identified by the U.S. Preventive Services Task Force (USPSTF), an independent panel of national experts in prevention and evidence-based medicine that makes evidence-based recommendations about clinical preventive services. The USPSTF assigns a letter grade (A, B, C, D, or I) to each recommendation based on the strength of the evidence and the balance of benefits and harms of the service. An I statement is the USPSTF’s conclusion that the current evidence is insufficient to recommend for or against the service.

Our objective is to describe the types of research gaps embodied in current USPSTF I statements and disseminate these gaps across the broader research community. We also point researchers to information published in USPSTF recommendation statements and evidence reports that can be used to design new research that addresses critical gaps.

Methods: We searched the 95 published recommendations of the USPSTF for I statements. We then distilled the specific research needs for each I statement and disseminated these identified gaps to internal and external stakeholders using the RAND Model of Persuasive Communication, as well as elements of Diffusion of Innovations theory.

Results: Forty-two I statements covering a broad range of preventive services were identified. Research gaps contributing to the USPSTF’s I recommendations included the need for trials of intervention efficacy, studies of effectiveness and health outcomes (including harms), and studies assessing intervention implementation in busy clinical practice settings.

Conclusions: Dissemination of I statements within NIH and to the extramural research community helps inform NIH funding policies and encourages new research to address critical knowledge gaps. Application of existing D&I models facilitates this knowledge transfer. By generating evidence to fill I statement research gaps, researchers can contribute to USPSTF efforts to make recommendations that are based on the most current, highest-quality evidence. Widespread implementation of these recommendations in clinical practice can ultimately lead to improved population health.