An empirical examination of Bradford's law and the scattering of scientific literature

Twenty‐three data sets representing the documents retrieved by a wide variety of searches were examined for correspondence to Bradford's Law. Regression lines fit to the data sets showed all correlations in excess of 0.96. Thus, the fitted line, as customarily specified by slope and intercept, can serve as a good representation of an entire data set. Slope can be shown to be almost entirely determined by the total number of articles retrieved. Over two‐thirds of the variance in the intercept is accounted for by the total number of journal titles retrieved. These findings weigh against earlier speculation that slope and intercept depended on such characteristics as breadth of subject area, topic, time period, or search technique. The findings show that Bradford's Law is the reflection of some underlying process not related to the characteristics of the search mechanism or the nature of the literature. The authors conclude that there is instead a basic probabilistic mechanism underlying the law.