Library journal use and citation age in medical science

This study explores the in-house use age distribution of journals in the library of Veterans General Hospital, Taipei, Taiwan, their citation age distribution and the difference between them. The use study employed the sweep method and the study period lasted for six months. The citation age of each journal in this study was based on the data listed in the Science Citation Index, Journal Citation Reports, 1993. The results of this study illustrate that the use age distribution for the mean of all the journals is an exponentially decaying curve. On the other hand, the citation age distributions show a sharp initial rise from age one to three or four years and then fall off in a sort of exponential decay; and the age of maximum citation is typically three years. About 80% of uses are attributed to journals less than ten years old, while these journals contribute about 70% of total citations. The Kolmogorov-Smirnov two-sample test indicates that the use age distribution does not fit the citation age distribution.