  According to current research in bibliometrics, percentiles (or percentile
rank classes) are the most suitable method for normalising the citation counts
of individual publications in terms of the subject area, the document type and
the publication year. Up to now, bibliometric research has concerned itself
primarily with the calculation of percentiles. This study suggests how
percentiles can be analysed meaningfully for an evaluation study. Publication
sets from four universities are compared with each other to provide sample
data. These suggestions take into account on the one hand the distribution of
percentiles over the publications in the sets (here: universities) and on the
other hand concentrate on the range of publications with the highest citation
impact - that is, the range which is usually of most interest in the evaluation
of scientific performance.
