Sampling and concentration values of incomplete bibliographies

This paper studies concentration aspects of bibliographies. More in particular we study the impact of incompleteness of such a bibliography on its concentration values (i.e. its degree of inequality of production of its sources). Incompleteness is modelled by sampling in the complete bibliography. The model is general enough to comprise truncation of a bibliography as well as a perfectly stratified sample on sources or items. In all cases we prove that the sampled bibliography (or incomplete one) has a higher concentration value than the complete one. These models hence shed some light on the measurement of production inequality in incomplete bibliographies. 'Permanent address Acknowledgement : the author is grateful to prof Dr. R. Rousseau for interesting discussions on the topic of this paper.