A double dissociation between impact factor and cited half life

A journal impact factor (IF) is calculated as the ratio between the number of citations in a given year to any item published in that journal in the previous two years and the number of research items published in the same journal in the same two years. Currently, neuropsychology journals are not ranked within their own category but are listed together with other disciplines. Neuropsychology is a typical slow-pace and interdisciplinary topic; hence authors may choose to submit their papers to mainstream neuropsychology journals as well as to neuroscience or clinical neurology journals. One way to examine this issue is to compare the IF for neuropsychology and neuroscience and contrast this with the cited half-life (CHL) for these two disciplines. This is what was done by Delia Sala and Crawford (2006) using the IF and CHL figures for 2004. The 2005 figures were used to compare the IFs and CHLs for neuropsychology and neuroscience using the same set of five journals from each discipline previously examined by Delia Sala and Crawford (2006).