Measuring dispositional optimism in student Veterans: An item response theory analysis

Background: The psychometric properties of the Life Orientation Test-Revised (LOT-R) have been established among college students, yet psychometric evidence is lacking for a sample of student Veterans in postsecondary education.Aims: The purpose of this study was to evaluate psychometric properties of the LOT-R for the assessment of dispositional optimism in student Veterans by using classical test theory (CTT) in conjunction with item response theory (IRT).Method: A sample of 205 student Veterans were recruited from universities across the United States. Exploratory factor analysis was conducted to test the unidimensionality of the LOT-R. A polychotomous IRT model using graded response model (GRM) was estimated. Reliability and concurrent validity of the LOT-R were tested.Results: CTT in conjunction with IRT validated that the LOT-R is a psychometrically sound unidimensional instrument for assessing the levels of dispositional optimism in student Veterans. The LOT-R was found to be associated wit...