Coauthorship trends in the leading radiological journals

Coauthorship trends have received limited attention in radiology. This paper examines the author inflation phenomenon in 12 leading radiological peer-reviewed journals and seeks explanations for the rise in multiple authorship. MEDLINE was searched from 1966 through 1991, and the indexed scientific material (67,758 articles) of the eligible core journals was analysed. During this 26-year period the average number of authors per original article (including case reports) doubled, increasing from 2.2 in 1966 to 4.4 in 1991. The linear regression model fitting the data was strongly significant, although since the late 1980s the rate of the coauthorship rise started to decrease. There was considerable variation in coauthorship patterns between journals. Other factors, such as the contributors' country, were also noted to influence coauthorship. The increasing complexity of radiological research explains in part the rise in multiple-author papers, but the main cause must undoubtedly be the excessive pressure to publish. Among the topics discussed are the incentives that stimulate radiologists to write, the dynamics of coauthorship, and the proposals made to standardize the requirements for authorship and to shift the emphasis from quantity of publication to quality.