In recent studies the issue of the relatedness between journal impact factors and other measures of journal impact have been
raised and discussed from both merely empirical and theoretical perspectives. Models of the underlying citation processes
suggest distributions with two or more free parameters. Proceeding from the relation between the journals’ mean citation rate
and uncitedness and the assumption of an underlying Generalised Waring Distribution (GWD) model, it is found that the journal
impact factor alone does not sufficiently describe a journal’s citation impact, while a two-parameter solution appropriately
reflects its main characteristics. For the analysis of highly cited publications an additional model derived from the same
GWD is suggested. This approach results in robust, comprehensible and interpretable solutions that can readily be applied
in evaluative bibliometrics.