title: Statistical methods used in articles published by the Journal of Periodontal and Implant Science.
abstract: OBJECTIVE
  The purposes of this study were to assess the trend of use of statistical methods including parametric and nonparametric methods and to evaluate the use of complex statistical methodology in recent periodontal studies.
  
  
  METHODS
  This study analyzed 123 articles published in the Journal of Periodontal & Implant Science (JPIS) between 2010 and 2014. Frequencies and percentages were calculated according to the number of statistical methods used, the type of statistical method applied, and the type of statistical software used.
  
  
  RESULTS
  Most of the published articles considered (64.4%) used statistical methods. Since 2011, the percentage of JPIS articles using statistics has increased. On the basis of multiple counting, we found that the percentage of studies in JPIS using parametric methods was 61.1%. Further, complex statistical methods were applied in only 6 of the published studies (5.0%), and nonparametric statistical methods were applied in 77 of the published studies (38.9% of a total of 198 studies considered).
  
  
  CONCLUSIONS
  We found an increasing trend towards the application of statistical methods and nonparametric methods in recent periodontal studies and thus, concluded that increased use of complex statistical methodology might be preferred by the researchers in the fields of study covered by JPIS.
authors.affiliation: BK21 PLUS Program in Embodiment: Health-Society Interaction, Department of Public Health Sciences, Graduate School, Korea University, Seoul, Korea.
authors.forename: Eunsil
authors.identifier: 0000-0003-0320-9638
authors.initials: E
authors.lastname: Choi
authors.affiliation: BK21 PLUS Program in Embodiment: Health-Society Interaction, Department of Public Health Sciences, Graduate School, Korea University, Seoul, Korea.
authors.forename: Jiyoung
authors.identifier: 0000-0002-7228-4212
authors.initials: J
authors.lastname: Lyu
authors.affiliation: BK21 PLUS Program in Embodiment: Health-Society Interaction, Department of Public Health Sciences, Graduate School, Korea University, Seoul, Korea.
authors.forename: Jinyoung
authors.identifier: 0000-0002-8762-6908
authors.initials: J
authors.lastname: Park
authors.affiliation: BK21 PLUS Program in Embodiment: Health-Society Interaction, Department of Public Health Sciences, Graduate School, Korea University, Seoul, Korea. ; Department of Health Policy and Management, College of Health Sciences, Korea University, Seoul, Korea.
authors.forename: Hae-Young
authors.identifier: 0000-0003-2043-2575
authors.initials: HY
authors.lastname: Kim
keywords: Nonparametric statistics; Periodontal diseases; Statistical data interpretation; Statistics