Citation counts by track.

Data from October 2006 (A) and May 2009 (B). Contributed papers are cited significantly less on average than Direct submissions or Communicated papers. Citation count distributions for each Track are shown in Text S1. The median 2006 citation count is 11 for Direct submissions, 11 for Communicated papers, and 9.5 for Contributed papers. The median 2009 citation count is 32.5 for Direct submissions, 31 for Communicated papers, and 28 for Contributed papers. Error bars indicate standard error of the mean. Note that the mean and the standard error of the mean are calculated from log10-transformed citation counts.