The uncitedness factor of a journal is its fraction of uncited articles. Given a set of journals (e.g. in a field) we can
determine the rank-order distribution of these uncitedness factors. Hereby we use the Central Limit Theorem which is valid
for uncitedness factors since it are fractions, hence averages. A similar result was proved earlier for the impact factors
of a set of journals. Here we combine the two rank-order distributions, hereby eliminating the rank, yielding the functional
relation between the impact factor and the uncitedness factor. It is proved that the decreasing relation has an S-shape: first
convex, then concave and that the inflection point is in the point (μ′, μ) where μ is the average of the impact factors and
μ′ is the average of the uncitedness factors.