title: The accuracy of the Life Orientation Test-Revised (LOT-R) in measuring dispositional optimism: evidence from item response theory analyses.
abstract: The accuracy of the Life Orientation Test-Revised (LOT-R) in measuring dispositional optimism was investigated applying item response theory (IRT). The study was conducted on a sample of 484 university students (62% males, M age = 22.79 years, SD = 5.63). After testing the 1-factor structure of the scale, IRT was applied to evaluate the functioning of the LOT-R along the pessimism-optimism continuum. Item parameter estimates and the test information function showed that each item and the global scale satisfactorily measured the latent trait. Referring to the IRT estimated trait levels, the validity of the LOT-R was studied examining the relationships between dispositional optimism and psychological well-being, sense of mastery, and sense of coherence. Overall findings based on IRT analyses provide evidence of the accuracy of the LOT-R and suggest possible modifications of the scale to improve the assessment of dispositional optimism.
authors.affiliation: Department of Psychology, University of Florence, Italy. francesca.chiesi@unifi.it
authors.forename: Francesca
authors.initials: F
authors.lastname: Chiesi
authors.forename: Silvia
authors.initials: S
authors.lastname: Galli
authors.forename: Caterina
authors.initials: C
authors.lastname: Primi
authors.forename: Paolo
authors.initials: P
authors.lastname: Innocenti Borgi
authors.forename: Andrea
authors.initials: A
authors.lastname: Bonacchi
mesh_terms: D000293:Adolescent; D000328:Adult; D000339:Affect; D005260:Female; D006801:Humans; D008297:Male; D010549:Personal Satisfaction; D010551:Personality; D010552:Personality Assessment; D060685:Sense of Coherence