Citation time window choice for research impact evaluation

• Published in: Scientometrics Vol. 94; no. 3; pp. 851 - 872
• Main Author: Wang, Jian
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.03.2013; Springer
• Subjects: Bibliometrics. Scientometrics; Bibliometrics. Scientometrics. Evaluation; Citations; Computer Science; Evaluation; Exact sciences and technology; Information and communication sciences; Information science. Documentation; Information Storage and Retrieval; Library and information science. General aspects; Library Science; Sciences and techniques of general use; Subject fields; Time factors; Citation ageing; Research evaluation; Field normalization; Citation time window; Research field; Self citation; Periodical; Scientific research; Citation
• ISSN: 0138-9130; 1588-2861
• DOI: 10.1007/s11192-012-0775-9

This paper aims to inform choice of citation time window for research evaluation, by answering three questions: (1) How accurate is it to use citation counts in short time windows to approximate total citations? (2) How does citation ageing vary by research fields, document types, publication months, and total citations? (3) Can field normalization improve the accuracy of using short citation time windows? We investigate the 31-year life time non-self-citation processes of all Thomson Reuters Web of Science journal papers published in 1980. The correlation between non-self-citation counts in each time window and total non-self-citations in all 31 years is calculated, and it is lower for more highly cited papers than less highly cited ones. There are significant differences in citation ageing between different research fields, document types, total citation counts, and publication months. However, the within group differences are more striking; many papers in the slowest ageing field may still age faster than many papers in the fastest ageing field. Furthermore, field normalization cannot improve the accuracy of using short citation time windows. Implications and recommendations for choosing adequate citation time windows are discussed.