Associations Between NIH Funding and Advanced Bibliometric Indices Among Radiological Investigators

Whereas data support the h index (reflecting both publications and citations) as an indicator of academic productivity, other advanced bibliometric indices aiming to address shortcomings of the h index remain poorly studied. Our objective was to compare the associations between bibliometric indices and total National Institutes of Health (NIH) grant funding among investigators within U.S. academic radiology departments.

NIH grant funding amounts for 400 NIH-funded investigators within radiology departments were obtained from Blue Ridge Institute for Medical Research. Investigators' publications and associated citations were identified using Scopus. Indices computed for each investigator included: publication count, citation count, h index, i-10 index, hc index (h index adjusted for recency of publications), m quotient (h index adjusted for career duration), and e index and g index (both account for highly cited articles). Spearman correlations were performed between indices and funding. Multivariable linear regression was performed to identify significant independent predictors of funding.

For MD investigators: the indices exhibited no-to-weak correlations with funding (r = 0.173-0.387); m quotient exhibited the largest correlation and was the only significant (albeit weak) independent predictor of funding (P = 0.011). For PhD investigators: correlation with funding was weak for m quotient (r = 0.323), although moderate for other indices (r = 0.518-0.568); publication count exhibited highest correlation; publication count (P < 0.001) and hc index (P = 0.024) were significant independent predictors of funding.

Bibliometric indices were more strongly associated with grant funding for PhD than for MD radiology investigators, with publication count exhibiting the strongest association in the latter group. Time-weighted adjustments, as reflected by the m quotient and hc index, may improve efforts to predict funding using bibliometrics.