Student well‐being is a growing issue in higher education, and assessment of the prevalence of conditions as loneliness is therefore important. In higher education and population surveys the Three‐Item Loneliness Scale (T‐ILS) is used increasingly. The T‐ILS is attractive for large multi‐subject surveys, as it consists of only three items (derived from the UCLA Loneliness Scale). Several ways of classifying persons as lonely based on T‐ILS scores exist: dichotomous and trichotomous classification schemes and use of sum scores with rising levels indicating more loneliness. The question remains whether T‐ILS scores are comparable across the different population groups where they are used or across groups of students in the higher education system. The aim was to investigate whether the T‐ILS suffers from differential item functioning (DIF) that might change the loneliness classification among higher education students, using a large sample just admitted to 22 different academy profession degree programs in Denmark (N = 3,757). DIF was tested relative to degree program, age groups and gender. The framework of graphical loglinear Rasch models was applied, as this allows for adjustment of sum scores for uniform DIF, and thus for assessment of whether DIF might change the classification. Two items showed DIF relative to degree program and gender, and adjusting for this DIF changed the classification for some subgroups. The consequences were negligible when using a dichotomous classification and larger when using a trichotomous classification. Therefore, trichotomous classification should be used with caution unless suitable adjustments for DIF are done prior to classification.

Self-efficacy is associated with both academic performance and attrition in higher education. Whether it is possible to measure students' academic self-efficacy after admission and prior to commencing higher education (i.e. pre-academic self-efficacy) in a valid and reliable way has hardly been studied. Aims: 1) to evaluate the construct validity and psychometric properties of two short scales to measure Pre-Academic Learning Self-Efficacy (PAL-SE) and Pre-Academic Exam Self-Efficacy (PAE-SE) using Rasch measurement models, 2) to investigate whether pre-academic self-efficacy was associated with half-year attrition across degree programs and institutions. Data consisted of 2686 Danish students admitted to nine different university degree programs across two institutions. Item analyses showed both scales to be essentially objective and construct valid, however, all items from the PAE-SE and two from the PAL-SE were locally dependent. Differential item functioning was found for the PAL-SE relative to degree programs. Reliability of the PAE-SE was .77, and varied for the PAL-SE from .79 to .86 across degree programs. Targeting was good only for the PAL-SE, thus we proceeded with the PAL-SE. PAL-SE was found to be associated with half-year attrition: A difference in PAL-SE from minimum to maximum was associated with a difference in half-year attrition of approximately 7%. This association was found both in the bivariate model and in the multivariate models with control of degree program, and with control of degree program and individual covariates such as earlier educational achievement and social background variables. Results thus also indicate that PAL-SE has a causal effect on half-year attrition.