Exploring Psychometric Complexities in Intensive Longitudinal Data
Holger Brandt, 30 July 2025, 18:30

In this talk, I will address problems that arise when researchers collect longitudinal data and present the same items repeatedly. Questions that may arise are: How often should I present the questionnaire? Can I find out when participants become inattentive? What happens if an item changes its meaning for persons who responded to it very often? I will discuss these psychometric questions that accompany the collection of intensive longitudinal data, for example in ecological momentary assessments. In many situations, psychometric characteristics obtained from cross-sectional evaluations of questionnaires may be difficult to extrapolate to such longitudinal studies that use repeated measures in a high-frequency (such as once per day or more). I will provide different examples, including heterogeneous measurement invariance patterns that may vary across persons and/