This chart shows the 2-Year Impact (review-only) of Progress in Polymer Science over time and its percentile among journals. Only review articles are counted in both the numerator (citations) and denominator (citable items).
The 2-year review impact for year X equals the citations received in year X to review articles published in years X-1 and X-2, divided by the number of review articles published in those two years. Unlike the standard 2-year impact, only items classified as review articles are counted in both the numerator and denominator.
