  It is becoming ever more common to use bibliometric indicators to evaluate
the performance of research institutions, however there is often a failure to
recognize the limits and drawbacks of such indicators. Since performance
measurement is aimed at supporting critical decisions by research
administrators and policy makers, it is essential to carry out empirical
testing of the robustness of the indicators used. In this work we examine the
accuracy of the popular "h" and "g" indexes for measuring university research
performance by comparing the ranking lists derived from their application to
the ranking list from a third indicator that better meets the requirements for
robust and reliable assessment of institutional productivity. The test
population is all Italian universities in the hard sciences, observed over the
period 2001-2005. The analysis quantifies the correlations between the three
university rankings (by discipline) and the shifts that occur under changing
indicators, to measure the distortion inherent in use of the h and g indexes
and their comparative accuracy for assessing institutions.
