  Quantitative bibliometric indicators are widely used to evaluate the
performance of scientists. However, traditional indicators do not much rely on
the analysis of the processes intended to measure and the practical goals of
the measurement. In this study, I propose a simple framework to measure and
predict an individual researcher's scientific performance that takes into
account the main regularities of publication and citation processes and the
requirements of practical tasks. Statistical properties of the new indicator -
a scientist's personal impact rate - are illustrated by its application to a
sample of Estonian researchers.
