Assessing the true role of coauthors in the hh-index measure of an author scientific impact

• The impact of co-authorship should give a hh-index measure higher than usually accepted.
• Examples of real teams with various authors who have sometimes published together are used
• The results point to a proof outlining how the weight of co-authors can be obtained.
• Interpretation is based on the statistical aspects of bibliometrics indices.
• This Principal Component Analysis is the method to be used.

A method based on the classical principal component analysis leads to demonstrate that the role of co-authors should give a hh-index measure to a group leader higher than usually accepted. The method rather easily gives what is usually searched for, i.e. an estimate of the role (or “weight”) of co-authors, as the additional value to an author papers’ popularity. The construction of the co-authorship popularity HH-matrix is exemplified and the role of eigenvalues and the main eigenvector component are discussed. Examples illustrate the points and serve as the basis for suggesting a generally practical application of the concept.