摘要:Scientometric assessments have become an essential component of research evaluation, and central to these is the use of citation indicators. Citations are used in the performance measurement of research departments and institutions1 , assessment of research funding applications2 , and promotion and hiring of research scientists3 . Although there have been strong arguments for and against the use of citations for these purposes due to concerns about their reliability and validity as performance indicators, most research institutions across the world continue to make decisions partly based on citation data.4 Citation counts are still widely used to judge scientific impact and quality, but the significant field-related and temporal variations that exist within the data make comparisons based on absolute counts inappropriate unless done with normalisation.