  The web application presented in this paper allows for an analysis to reveal
centres of excellence in different fields worldwide using publication and
citation data. Only specific aspects of institutional performance are taken
into account and other aspects such as teaching performance or societal impact
of research are not considered. Based on data gathered from Scopus,
field-specific excellence can be identified in institutions where highly-cited
papers have been frequently published. The web application combines both a list
of institutions ordered by different indicator values and a map with circles
visualizing indicator values for geocoded institutions. Compared to the mapping
and ranking approaches introduced hitherto, our underlying statistics
(multi-level models) are analytically oriented by allowing (1) the estimation
of values for the number of excellent papers for an institution which are
statistically more appropriate than the observed values; (2) the calculation of
confidence intervals as measures of accuracy for the institutional citation
impact; (3) the comparison of a single institution with an "average"
institution in a subject area, and (4) the direct comparison of at least two
institutions.
