The SCI Journal Citation Reports: A potential tool for studying journals? .1. Description of the JCR journal population based on the number of citations received, number of source items, impact factor, immediacy index and cited half-life

In this paper, we analysed six indicators of the SCI Journal Citation Reports (JCR) over a 19-year period: number of total citations, number of citations to the two previous years, number of source items, impact factor, immediacy index and cited half-life. The JCR seems to have become more or less an authority for evaluating scientific and technical journals, essentially through its impact factor. However it is difficult to find one's way about in the impressive mass of quantitative data that JCR provides each year. We proposed the box plot method to aggregate the values of each indicator so as to obtain, at a glance, portrayals of the JCR population from 1974 to 1993. These images reflected the distribution of the journals into 4 groups designated low, central, high and extreme. The limits of the groups became a reference system with which, for example, it was rapidly possible to situate visually a given journal within the overall JCR population. Moreover, the box plot method, which gives a zoom effect, made it possible to visualize a large sub-population of the JCR usually overshadowed by the journals at the top of the rankings. These top level journals implicitly play the role of reference in evaluation processes. This often incites categorical judgements when the journals to be evaluated are not part of the top level. Our <<rereading>> of the JCR, which presented the JCR product differently, made it possible to qualify these judgements and bring a new light on journals.