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George Barnett, Edward think, and Mary Beth debus constructed a mathematical model of citation age to test this ordering using large data sets from each of the science citation index, social sciences citation index, and arts and humanities citation index published by the isi. In each of these three sets, the citation age of an average article reaches its peak in less than two years, with the Arts and Humanities peeking soonest parentheses 1.164 years close parentheses comma and the social sciences speaking latest parentheses 1.752 years close parentheses, contrary to expectations. The maximum proportion of citations did have the predicted ordering, with science the highest, and the Arts and Humanities the lowest. While the models presume that citation rates were stable over time a close examination of the data revealed that citation for article increase substantially over the time period of the study parentheses in science, from 12.14 per article in 1961 to 16 in 1986 God semi colon in the social sciences, from 7.07 in 1970 to 15.6 in 1986 semi colon no Citation for article data were given for the Arts and Humanities close parentheses.