Citation metrics are the best tools for research assessments. However,
current metrics are misleading in research systems that pursue simultaneously
different goals, such as the advance of science and incremental innovations,
because their publications have different citation distributions. We estimate
the contribution to the progress of knowledge by studying only a limited number
of the most cited papers, which are dominated by publications pursuing this
progress. To field-normalize the metrics, we substitute the number of citations
by the rank position of papers from one country in the global list of papers.
Using synthetic series of lognormally distributed numbers, we developed the
Rk-index, which is calculated from the global ranks of the 10 highest numbers
in each series, and demonstrate its equivalence to the number of papers in top
percentiles, P top 0.1% and P top 0.01% . In real cases, the Rk-index is simple
and easy to calculate, and evaluates the contribution to the progress of
knowledge much better than commonly used metrics. Although further research is
needed, rank analysis of the most cited papers is a promising approach for
research evaluation. It is also demonstrated that, for this purpose, domestic
and collaborative papers should be studied independently.Comment: One PDF file, including figures and tables (31 pages