The present study is to evaluate cataloguing consistency in Tehran’s academic and research libraries compared to that in the National Library of Iran. In order to limit the library collections, the subject category of “Iran logy” has been selected out of 12 relevant academic and research libraries. Using content analysis and survey methods, the data of the library catalogs from 1983 up to 1997 were noted down on specil sheets and then they calculated and analysed based on their main entries, subject headings, and classification codes. Data was analysed using statistical tables as well as Hooper formula. The findings of the preset study indicate that in 66.6% of libraries there is less than 50% inconsistency in main entries, whereas in 33.3% of them the inconsistency rate is between 65.5% and 87/5% In terms of subject headings, in 75% of libraries the inconsistency rate is between 60% and 85%. In 91.5% of libraries there is more than 50% inconsistency in classification. The most inconsistency rate of main entry belongs to the library of Danesh Pajouh and the least one belongs to the library of Humanties Research Center. The most inconsistency rate of subject headings belongs to the Art Faculty library and the least one belongs to the Humanities Research Center; whereas the most inconsistency rate in classification belongs to the International Study Center library and the least one is for the Parliament Library. The findings also indicate that, in terms of DDC Classification, the most inconsistency rate of main entries belong to the class of literature, the most one in subject headings and classification belong to the class of Philosophy. Summing up the findings, we can find that the total inconsistency rate in classification(73.37%) is more than the rate of subject headings(71 %) which, in turn, is more than the rate of main entry(50.8%).
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