Summary of statistics in American Journal of Orthodontics and Dentofacial Orthopedics articles published in 2003

Introduction: From 1975 to 1985, the percentage of articles published in the American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO) reporting statistical methods nearly doubled, from 43% to 76%. The increase was mainly due to the greater use of inferential statistics. The purpose of this report was to assess the statistical procedures used in articles published in the journal nearly 20 years later in 2003. Methods: All 205 articles published in the journal in 2003 were divided into 2 groups: original research reports and other (including case reports, editorials, and legal articles). The frequency and distribution of statistics used in the original research articles were recorded. Results: The journal published 134 original articles in 2003. Four reported no statistical procedures and the other 130 reported 284 statistical procedures. Ten procedures were descriptive, 265 were inferential, and 9 were miscellaneous. The inferential methods included 163 parametric, 72 nonparametric, and 30 posthoc analyses. Conclusions: Most (94%) original articles published in the AJO-DO in 2003 reported statistical methods. Most (93%) used inferential methods rather than descriptive. The inferential methods were more likely to be nonparametric than parametric.