Outlier Detection in Test and Questionnaire Data

Autor/inn/en	Zijlstra, Wobbe P.; Van Der Ark, L. Andries; Sijtsma, Klaas
Titel	Outlier Detection in Test and Questionnaire Data
Quelle	In: Multivariate Behavioral Research, 42 (2007) 3, S.531-555 (25 Seiten) PDF als Volltext Verfügbarkeit
Sprache	englisch
Dokumenttyp	gedruckt; online; Zeitschriftenaufsatz
ISSN	0027-3171
Schlagwörter	Rating Scales; Scores; Regression (Statistics); Statistical Analysis; Questionnaires; Data; Tests; Methods Research; Behavioral Science Research; Psychometrics; Multivariate Analysis; Research Problems; Experimenter Characteristics; Robustness (Statistics) + Suchen Sie Ihr Suchwort? Rating-Skala; Regression; Regressionsanalyse; Statistische Analyse; Fragebogen; Daten; Examination; Prüfung; Examen; Methodenforschung; Psychometry; Psychometrie; Multivariate Analyse; Forschungskritik; Widerstandsfähigkeit
Abstract	Classical methods for detecting outliers deal with continuous variables. These methods are not readily applicable to categorical data, such as incorrect/correct scores (0/1) and ordered rating scale scores (e.g., 0,..., 4) typical of multi-item tests and questionnaires. This study proposes two definitions of outlier scores suited for categorical data. One definition combines information on outliers from scores on all the items in the test, and the other definition combines information from all pairs of item scores. For a particular item-score vector, an outlier score expresses the degree to which the item-score vector is unusual. For ten real-data sets, the distribution of each of the two outlier scores is inspected by means of Tukey's fences and the extreme studentized deviate procedure. It is investigated whether the outliers that are identified are influential with respect to the statistical analysis performed on these data. Recommendations are given for outlier identification and accommodation in test and questionnaire data. (Contains 4 tables and 2 figures.) (Author).
Anmerkungen	Lawrence Erlbaum. Available from: Taylor & Francis, Ltd. 325 Chestnut Street Suite 800, Philadelphia, PA 19106. Tel: 800-354-1420; Fax: 215-625-2940; Web site: http://www.tandf.co.uk/journals/default.html
Erfasst von	ERIC (Education Resources Information Center), Washington, DC
Update	2017/4/10