Systematic differences in impact across publication tracks at PNAS Supporting Information S1

Systematic differences in impact across publication tracks at PNAS Supporting Information S1 David G Rand1,2* & Thomas Pfeiffer1 Program for Evolutionary Dynamics and 2Berkman Center for Internet and Society, Harvard University, Cambridge MA 02138 Contents Summary statistics Distribution of citation counts by Track Analysis of citation counts controlling for additional factors Analysis of page-views as of October 2006 Summary Statistics Table S1 Summary statistics N=2695 papers Variable log10(Citations2006+1) log10(Citations2009+1) log10(Pageviews2006) Age (Days relative to newest article) Submission track Topic classification Open Access Special Feature Levels Direct submission Communicated Contributed Agricultural Sciences Anthropology Applied Biological Sciences Biochemistry Biophysics and Computational Biology Cell Biology Developmental Biology Ecology Environmental Sciences Evolution Genetics Immunology Medical Sciences Microbiology Neuroscience Pharmacology Physiology Plant Biology Population Biology Psychology Physical Science Social Science Yes No Yes No Mean 1.048 1.492 3.403 Std Dev 0.355 0.358 0.230 162 98 44.3% 25.8% 29.9% 0.26% 0.41% 1.52% 12.62% 8.57% 7.42% 3.23% 2.08% 0.15% 5.05% 6.20% 5.97% 10.13% 6.60% 11.17% 1.60% 2.63% 3.27% 0.41% 0.82% 8.8% 1.1% 14.1% 85.9% 1.3% 98.7% Min 0 2.658 Max 2.626 2.989 4.669 329 Distribution of citation counts by Track Table S2 2006 Citation counts Direct Communicated 10% 3 25% 6 50% 11 11 75% 18 18 90% 28 30 Contributed 9.5 17 30 Table S3 2009 Citations counts Direct Communicated 10% 11 11 25% 20 19 50% 32.5 31 75% 51 53 90% 80 87 Contributed 15 28 51 87 Figure S1 Distributions of Log10(Citation06+1) (First column) and Log10(Citations2009+1) (Second Column) by Track 3 Analysis of citation counts controlling for additional factors Here we use regression to a standard linear model, with log-transformed citation counts as the dependent variable, and submission track, open access, special feature and field as independent variables Coefficients for Communicated and Contributed levels of submission track are relative to Direct submissions Coefficients for each subfield are relative to biochemistry (the most common subfield) Table S4 Regression on 2006 Citations Communicated Contributed Open Access Special Feature Age (Days relative to newest article) Agricultural Sciences Anthropology Applied Biological Sciences Biophysics and Computational Biology Cell Biology Developmental Biology Ecology Environmental Sciences Evolution Genetics Immunology Medical Sciences Microbiology Neuroscience Pharmacology Physiology Plant Biology Population Biology Psychology Physical Science Social Science Intercept Coefficient -0.010 -0.050 0.104 -0.022 0.0008 0.082 -0.184 0.040 0.069 0.089 0.021 -0.057 0.020 0.031 0.113 0.081 0.133 0.149 0.033 0.055 -0.018 0.101 -0.139 -0.139 -0.148 -0.364 0.880 Test statistic -0.63 -3.17 5.43 -0.39 12.43 0.58 -2.71 0.69 2.71 3.04 0.58 -1.05 0.12 0.91 3.75 2.47 5.23 4.92 1.32 1.03 -0.42 2.88 -1.40 -1.79 -4.61 -5.61 40.24 P-value 0.532 0.002