title: An Analysis of Peer-Reviewed Scores and Impact Factors with Different Citation Time Windows: A Case Study of 28 Ophthalmologic Journals.
abstract: BACKGROUND
  An important attribute of the traditional impact factor was the controversial 2-year citation window. So far, several scholars have proposed using different citation time windows for evaluating journals. However, there is no confirmation whether a longer citation time window would be better. How did the journal evaluation effects of 3IF, 4IF, and 6IF comparing with 2IF and 5IF? In order to understand these questions, we made a comparative study of impact factors with different citation time windows with the peer-reviewed scores of ophthalmologic journals indexed by Science Citation Index Expanded (SCIE) database.
  
  
  METHODS
  The peer-reviewed scores of 28 ophthalmologic journals were obtained through a self-designed survey questionnaire. Impact factors with different citation time windows (including 2IF, 3IF, 4IF, 5IF, and 6IF) of 28 ophthalmologic journals were computed and compared in accordance with each impact factor's definition and formula, using the citation analysis function of the Web of Science (WoS) database. An analysis of the correlation between impact factors with different citation time windows and peer-reviewed scores was carried out.
  
  
  RESULTS
  Although impact factor values with different citation time windows were different, there was a high level of correlation between them when it came to evaluating journals. In the current study, for ophthalmologic journals' impact factors with different time windows in 2013, 3IF and 4IF seemed the ideal ranges for comparison, when assessed in relation to peer-reviewed scores. In addition, the 3-year and 4-year windows were quite consistent with the cited peak age of documents published by ophthalmologic journals.
  
  
  CONCLUSIONS
  Our study is based on ophthalmology journals and we only analyze the impact factors with different citation time window in 2013, so it has yet to be ascertained whether other disciplines (especially those with a later cited peak) or other years would follow the same or similar patterns.
  We designed the survey questionnaire ourselves, specifically to assess the real influence of journals. We used peer-reviewed scores to judge the journal evaluation effect of impact factors with different citation time windows. The main purpose of this study was to help researchers better understand the role of impact factors with different citation time windows in journal evaluation.
authors: Periodicals Publishing House, Xinxiang Medical University, Xinxiang, Henan Province, China; Henan Research Center for Science Journals, Xinxiang Medical University, Xinxiang, Henan Province, China.
authors: Xue-Li
authors: XL
authors: Liu
authors: Henan Research Center for Science Journals, Xinxiang Medical University, Xinxiang, Henan Province, China.
authors: Shuang-Shuang
authors: SS
authors: Gai
authors: Henan Research Center for Science Journals, Xinxiang Medical University, Xinxiang, Henan Province, China.
authors: Shi-Le
authors: SL
authors: Zhang
authors: Xiamen University Tan Kan Kee College Library, Zhangzhou, Fujian Province, China.
authors: Pu
authors: P
authors: Wang
mesh_terms: D015706:Bibliometrics; D016206:Databases, Bibliographic; D006801:Humans; D055811:Journal Impact Factor; D009885:Ophthalmology; D017712:Peer Review, Research; D010506:Periodicals as Topic; D012107:Research Design; D011795:Surveys and Questionnaires; D013997:Time Factors