In this study, the impact factor of the cited dissertations have been measured in the US dissertations, being defended during 1978-2001 in Tehran public universities. To achieve the objectives of the study, citation analysis method was applied. The findings indicate that the citations of 473 dissertations were mostly book-based (59.8%). Dissertations also were cited about 9.96%(i,293 citations) from total cited materials. The average number of citations was 28. As regards the impact factor of dissertations, the study showed that those of Iran Medical Science University had the highest impact factor in 1993, followed by Tarbiat Modarress University in 1993, and Then University of Tehran in 1999. Concerning the half life of cited dissertations, those belonging to University of Tehran had the highest half life(9 Years) in 2001, and those of Tarbiat Modarress University had the lowest half life(2 months) in 1992.
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