The 2010 Asia–Pacific Publishing Index of the Nature Publishing Group (NPG) family of journals (http://go.nature.com/fqm8s3) analyses publication growth and research trends in this important and dynamic region. But omission of a crucial component of the analysis may have distorted its performance comparisons between countries.

The documented increase in NPG publications in the region for 2000–10 does not take into account the increase over that period in the number of articles per journal per year (see Scopus bibliographic database; http://www.scopus.com) or the rise in the number of NPG journals (from 7 to 17).

Comparing the percentage publication share of Japan and China in NPG journals between 2000–10 reveals that Japan's barely changed (increasing from 7.5% to about 9.5%). China's grew much faster (from 0.6% to 5%) over the period, indicative of a vibrant and expanding research community.

This picture is very different from the results presented in the supplement.