Intended for healthcare professionals

Open access publishing, article downloads, and citations: randomised controlled trial

Philip M Davis, Bruce V Lewenstein, Daniel H Simon, James G Booth, Mathew J L Connolly
Table 3

 Negative binomial regression output reporting independent variable effects on citations to articles aged 9 to 12 months

CoefficientIncidence rate ratio (95% CI)P value
Open access0.95 (0.81 to 1.10)0.484
Cover article0.93 (0.52 to 1.64)0.789
Press release1.23 (0.50 to 3.05)0.654
Self archived0.90 (0.53 to 1.55)0.716
Review article1.34 (1.01 to 1.78)0.041
Methods article0.62 (0.37 to 1.06)0.079
Any author from USA1.17 (1.04 to 1.32)0.007
No of authors*1.13 (1.01 to 1.26)0.030
No of references*1.42 (1.17 to 1.72)<0.001
Article length (pages)*1.09 (0.86 to 1.38)0.483
Journal impact factor*1.39 (1.10 to 1.76)0.006
Issue1.26 (1.20 to 1.33)<0.001

χ2 12, 1607=313.14, P<0.001, pseudo R2=0.06, α for dispersion 0.43 (95% confidence interval 0.35 to 0.54).

*Log transformed.