The paper discusses usage of citation indices and similar databases as the source of data for determining scientific professional advancement. A short study on per-author basis, using Web of Science, Scopus, Google Scholar, Croatian scientific bibliography and online catalogue of the National and University Library in Zagreb, has been undertaken and shows disparate results for usage of these resources in mentioned context. Various problems surrounding such studies are discussed. Data complementation, and especially firmer, more interconnected, national databases are recommended.