title: Appropriateness of reporting statistical results in orthodontics: the dominance of P values over confidence intervals.
abstract: The purpose of this study was to search the orthodontic literature and determine the frequency of reporting of confidence intervals (CIs) in orthodontic journals with an impact factor. The six latest issues of the American Journal of Orthodontics and Dentofacial Orthopedics, the European Journal of Orthodontics, and the Angle Orthodontist were hand searched and the reporting of CIs, P values, and implementation of univariate or multivariate statistical analyses were recorded. Additionally, studies were classified according to the type/design as cross-sectional, case-control, cohort, and clinical trials, and according to the subject of the study as growth/genetics, behaviour/psychology, diagnosis/treatment, and biomaterials/biomechanics. The data were analyzed using descriptive statistics followed by univariate examination of statistical associations, logistic regression, and multivariate modelling. CI reporting was very limited and was recorded in only 6 per cent of the included published studies. CI reporting was independent of journal, study area, and design. Studies that used multivariate statistical analyses had a higher probability of reporting CIs compared with those using univariate statistical analyses. Misunderstanding of the use of P values and CIs may have important implications in implementation of research findings in clinical practice.
authors.affiliation: Department of Preventive and Community Dentistry, School of Dentistry, University of Athens, Greece.
authors.forename: Argy
authors.initials: A
authors.lastname: Polychronopoulou
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Pandis
authors.forename: Theodore
authors.initials: T
authors.lastname: Eliades
mesh_terms: D000704:Analysis of Variance; D001294:Attitude to Health; D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D002986:Clinical Trials as Topic; D015331:Cohort Studies; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D018865:Dental Research / Q000706:statistics & numerical data*; D015438:Health Behavior; D006801:Humans; D055811:Journal Impact Factor; D016015:Logistic Models; D008310:Malocclusion / Q000175:diagnosis / Q000523:psychology / Q000628:therapy; D008445:Maxillofacial Development / Q000235:genetics / Q000502:physiology; D015999:Multivariate Analysis; D009910:Oral Hygiene; D009970:Orthodontics / Q000706:statistics & numerical data*; D010506:Periodicals as Topic / Q000706:statistics & numerical data; D011336:Probability
chemical_list: D001672:Biocompatible Materials