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Measuring science: an exploration
1Department of Economics, University of Florida, Gainesville 32611-7140, USA.
Summary
Academic research and development (R&D) spending shows diminishing returns when measuring output by papers or citations. New data suggest spillovers play a significant, unmeasured role in scientific productivity.
Area of Science:
- Economics of Science
- Science and Technology Policy
- Research and Development Management
Background:
- Academic research and development (R&D) expenditures are key indicators of scientific enterprise output.
- Previous analyses using Science and Engineering Indicators data suggested diminishing returns to R&D investment.
- Concerns existed regarding the accuracy and scope of existing data for measuring R&D productivity.
Purpose of the Study:
- To re-evaluate the relationship between academic R&D expenditures and scientific output using updated data.
- To investigate the presence and extent of diminishing returns in academic R&D.
- To identify potential measurement issues and the role of external factors in scientific productivity.
Main Methods:
- Analysis of United States academic R&D expenditures, publication counts, and citation data.
- Utilized a newer dataset encompassing a broader range of journals and updated R&D deflators from the Bureau of Economic Analysis.
- Applied production function analysis at the individual university field level, comparing R&D inputs with outputs (papers, citations) and considering scientists/engineers as alternative inputs.
Main Results:
- Updated data eliminate the apparent diminishing returns seen in earlier analyses.
- Academic R&D input prices have risen faster than general economic deflators.
- Production function analysis indicated diminishing returns to "own" R&D (coefficients ~0.5-0.6 for papers/citations).
- Substituting scientists and engineers for R&D as input improved coefficients but still suggested measurement issues.
- Accounting for university field-specific effects further reduced coefficients below unity, highlighting the importance of unmeasured factors.
Conclusions:
- The appearance of diminishing returns to academic R&D is largely an artifact of older data and measurement issues.
- Significant unmeasured contributions, likely from spillovers (interdisciplinary, inter-institutional, international), are crucial for scientific output.
- Further research is needed to quantify the impact of these spillovers on R&D productivity.
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