Presentation
Intensive longitudinal data with a large number of timepoints per individual are becoming increasingly common in psychological science, e.g., with mobile apps or wearable devices that can ask people questions or measure traits like sleep or stress at a high frequency. Such data allow going beyond the classical growth model situation and study population effects and individual variability not only in trends over time but in autoregressive effects, cross-lagged effects, and the noise term.
Dynamic structural equation models (DSEMs) have become very popular for analyzing intensive longitudinal data. However, when the data contain trends, cycles, or time-varying predictors which have nonlinear effects on the outcome, DSEMs require the practitioner to specify the correct parametric form of the effects, which may be challenging in practice. In this talk, ?ystein will present a paper in which they show how to alleviate this issue by introducing regression splines which are able to flexibly learn the underlying function shapes. Their main contribution is a building block to the DSEM modeler's toolkit, which makes the models applicable to a larger range of applications. This will be illustrated with simulation results and application examples.
Furthermore, he will discuss why Stan (https://mc-stan.org/) is a perfect tool for fitting these kinds of highly parametrized models, due to its scalable No-U-Turn Sampler, and demonstrate our particular implementation with code examples. Finally, ?ystein will briefly describe some of the interesting unsolved methodological questions related to analysis of intensive longitudinal data.
Speaker
?ystein S?rensen is Professor of Biostatistics at the Department of Psychology, University of Oslo. His research interests include methods and computational algorithms for analysis of longitudinal data, scientific software development, and use of machine learning in the social sciences.
Program
11:30 – Doors open and lunch is served
12:00 – "Modeling Cycles, Trends and Time-Varying Effects in Dynamic Structural Equation Models with Regression Splines" by ?ystein S?rensen (Professor, Department of Psychology)
This event is open for all students, PhD candidates, postdocs, and everyone else who is interested in the topic. No registration needed.
About the seminar series
Once a month, dScience will invite you to join us for lunch and professional talks at the Science Library. In addition to these, we will serve lunch in our lounge in Kristine Bonnevies house every Thursday. Due to limited space (40 people), this will be first come, first served. See how to find us here.
Our lounge can also be booked by PhDs and Postdocs on a regular basis, whether it is for a meeting or just to hang out – we have fresh coffee all day long!