Despite a “Cambrian” explosion in the number of citation metrics used(Van Noorden, 2010), the impact factor (IF) of a journal remains a decisive factor ofchoice when publishing your ultimate research results and evaluating researchproductivity. Most other citation metrics correlate with the IF and there is little doubtthat they reflect the overall impact of different journals. However, there is good reason tobe more cautious about IF judgements.First, the distribution of the number of citations per paper (NCPP) within a journalis heavily skewed. A few highly-cited papers often account for a significant amount of thetotal citation count of a journal (25 % of the papers in Nature account for 89 % of the IF“Not-so-deep impact”, 2005) and a recent report highlighted that even a single article candramatically bias the IF of a small journal (Dimitrov, Kaveri, & Bayry, 2010). The meanNCPP, as captured with the IF, should therefore never be used. A more appropriatemeasure is the median NCPP. Figure 1 (left) plots the median of the total NCPP againstthe mean, for three potential publication outlets for psychologists; Psychological Review(IF2009=9.1), Nature (IF2009=34.5) and Psychological Science (IF2009=5.1), for differentyears (data compiled from ISI Web of Knowledge). Nature follows a distinct trend whencompared to specialist journals: the median seems independent from its mean. Thisapparent dissociation results from the skew of the citation distribution observed inNature, in wh...