Over the past decades, the competition for academic resources has gradually
intensified, and worsened with the current financial crisis. To optimize the
resource allocation, individualized assessment of research results is being
actively studied but the current indices, such as the number of papers, the
number of citations, the h-factor and its variants have limitations, especially
their inability of determining co-authors' credit shares fairly. Here we
establish an axiomatic system and quantify co-authors' relative contributions.
Our methodology avoids subjective assignment of co-authors' credits using the
inflated, fractional or harmonic methods, and provides a quantitative tool for
scientific management such as funding and tenure decisions.