National scientific facilities and their science impact on nonbiomedical research

Abstract

The "h index" proposed by Hirsch [Hirsch JE (2005) Proc Natl Acad Sci USA 102:16569-16573] is a good indicator of the impact of a scientist's research and has the advantage of being objective. When evaluating departments, institutions, or laboratories, the importance of the h index can be further enhanced when it is properly calibrated for the size of the group. Particularly acute is the issue of federally funded facilities whose number of actively publishing scientists frequently dwarfs that of academic departments. Recently, Molinari and Molinari [Molinari JF, Molinari A (2008) Scientometrics, in press] developed a methodology that shows that the h index has a universal growth rate for large numbers of papers, allowing for meaningful comparisons between institutions. An additional challenge when comparing large institutions is that fields have distinct internal cultures, with different typical rates of publication and citation; biology is more highly cited than physics, for example. For this reason, the present study has focused on the physical sciences, engineering, and technology and has excluded biomedical research. Comparisons between individual disciplines are reported here to provide a framework. Generally, it was found that the universal growth rate of Molinari and Molinari holds well across the categories considered, testifying to the robustness of both their growth law and our results. The goal here is to set the highest standard of comparison for federal investment in science. Comparisons are made of the nation's preeminent private and public institutions. We find that many among the national science facilities compare favorably in research impact with the nation's leading universities.

Fig. 1.

Master curve for science disciplines. The h index is calculated for nonbiomedical publications for 10 years over a 19-year span from 1980 to 1998. The data are cumulative, including increments of even years of data, starting with 1980, then 1980 plus 1982, and so on, up to and including data for all even years from 1980 to 1998. Overlaid are encompassing lines with slope 0.4. Although the universal law with exponent ≈0.4 works well for physics, chemistry, and astronomy, it works less well for engineering and mathematics, where a somewhat lower exponent of the order of 0.35 might be more appropriate. Note that all figures in this article are shown with two decades on the x axis, Number of Papers, for ease of comparison. Consequently, some scientific fields in this plot show <10 data points because the fields have either <1,000 papers or >100,000 papers in the given years.

Fig. 2.

Master curve for a selection of top-ranked universities. The h index is calculated for nonbiomedical publications for the year 1980, 1980 plus 1982, and incrementing by even years through 1990. Template lines are carried over from Fig. 1. See SI Text and SI Table 7 for detailed methodology.

Fig. 3.

Master curves for selected public universities. The most remarkable aspect of the impact index for these universities is the narrow dispersion of the curves and the impact indices, as shown in Table 3.

Fig. 4.

Master curves for the even and odd years for Ohio State University. Note that although the two data sets have no overlapping publications, the two master curves track very closely.

Fig. 5.

Master curves for five NASA science centers.

Fig. 6.

Master curves for DOE national laboratories plus CERN.

Fig. 7.

Master curves for certain NSF science facilities plus the STScI.

Fig. 8.

Master curves for universities, shown together with curves for NASA and DOE.