Resumen de The 5-year synchronous impact factor for large Journal Citation Reports (JCR) subject areas
Using the largest JCR Thomson Reuters subject areas it is shown that the two-year and the five-year impact factor of journals lead statistically to the same ranking per category. This observation holds for top journals as well as lower level journals. Yet in a majority of cases the 5-year impact factor is larger than the 2-year one. A special case was observed in which one article influenced macro statistics of a whole journal subject category.
