This paper investigates the characteristics of the Journal Citation
Reports (JCR) through the study of the Science Citation Index (SCI). Other
criteria for evaluating a journal are also discussed. The compilation process of
SCI data, characteristics, applications and limitations of SCI are studied. A
detail description of JCR is provided including: journal ranking listing, citing
jouranl listing, cited journal listing, subject category listing, source data,
impact factor, immediacy index, cited half-life and citing half-life. Moreover,
applications and limitations of JCR are also explored. In addition to the
criteria listed in JCR, the size, circulation and influence of journals are also
significant criteria for journal evaluation.