Objective To determine any bias by authors of different nationalities in their citation rate of selected urological journals in papers published in the British Journal of Urology and the journal of Urology. Methods Using a simple computer program and text files of accepted reports in the BJU. or those available on CD-ROM from J Urol. 212 recent papers in the BJU and 111 from J Urol were analysed to determine the number of citations to four major urological journals (BJU, J Urol. Eur Urol and Urology). The frequencies of citations to these journals were then compared with the national origin of the author(s), grouped as UK, Europe, North America and Other. Results In both the BJU and J Urol the citation rates of the selected journals differed significantly among authors from different regions. In BJU papers, the citation rate of the BJU was highest by UK authors and their citation rate of J Urol was amongst the lowest of the rates for J Urol, The highest citation rate for J Urol was that by European authors. American authors cited the BJU least, citing the J Urol about five times more often than they cited the BJU. Of the papers in the J Urol sample, over 60% were from American authors, with only four from UK authors; thus the UK group was not analysed separately but included in the European group. The mean citation rate of J Urol was highest in papers by American authors, at about 14 times that for citations to the BJU. The citation rates for the other two journals were not significantly different with nationality or journal, but were generally much lower in J Urol than in the BJU. Conclusion There are significant differences in citation rates both with authors' nationality and between journals. Citation rates may be influenced by journal accessibility, perceived journal 'prestige' (impact factor) or national bias, Authors, editors and reviewers should be aware of this potential bias in citation habits. Authors should strive to conduct exhaustive searches using electronic methods, so that all relevant papers are assessed, regardless of their origin.
