title: Count data in psychological applied research.
abstract: As some authors have noticed in fields other than psychology, level of measurement and distributional characteristics of count data are commonly not taken into account, so that they are analysed as normally distributed continuous variables, and therefore some general linear model is applied. In this work, we review a random sample of 457 articles published in the last four years in journals with the highest impact factor in the Journal Citation Reports (JCR Social Sciences Edition) of the Institute for Scientific Information. The goals are to know how often count variables appear in psychological applied research and which data analyses are used when dealing with count response variables. Examination showed that there is a notable presence of count variables, especially in some topics in psychology and a remarkable misapplication of the general linear model. One deals with causes and consequences of this approach to data analysis and suggests the use of specific models to analyse count data.
authors.affiliation: Departament de Psyicobiologia i de Metodologia de les CC. de la Salut, Facultat de Psicologia, Campus de la Universitat Autònoma de Barcelona, 08193-Cerdanyola del Vallès, Barcelona, Spain. Jaume.Vives@UAB.es
authors.forename: Jaume
authors.initials: J
authors.lastname: Vives
authors.forename: Josep-Maria
authors.initials: JM
authors.lastname: Losilla
authors.forename: María-Florencia
authors.initials: MF
authors.lastname: Rodrigo
mesh_terms: D006801:Humans; D011585:Psychology, Applied / Q000379:methods* / Q000706:statistics & numerical data*