Metrics associated with NIH funding: a high-level view

OBJECTIVE To introduce the availability of grant-to-article linkage data associated with National Institutes of Health (NIH) grants and to perform a high-level analysis of the publication outputs and impacts associated with those grants. DESIGN Articles were linked to the grants they acknowledge using the grant acknowledgment strings in PubMed using a parsing and matching process as embodied in the NIH Scientific Publication Information Retrieval & Evaluation System system. Additional data from PubMed and citation counts from Scopus were added to the linkage data. The data comprise 2,572,576 records from 1980 to 2009. RESULTS The data show that synergies between NIH institutes are increasing over time; 29% of current articles acknowledge grants from multiple institutes. The median time lag to publication for a new grant is 3 years. Each grant contributes to approximately 1.7 articles per year, averaged over all grant types. Articles acknowledging US Public Health Service (PHS, which includes NIH) funding are cited twice as much as US-authored articles acknowledging no funding source. Articles acknowledging both PHS funding and a non-US government funding source receive on average 40% more citations that those acknowledging PHS funding sources alone. CONCLUSION The US PHS is effective at funding research with a higher-than-average impact. The data are amenable to further and much more detailed analysis.