I have 8 indicator variables and am wondering how best to assign them to a latent variable in lavaan. I have 6 indicator variables that were measured using a 7-point likert scale. The 2 other indicator variables consist of z-standardised variables. They describe the time in which a task was completed and how well this task was completed.

I conducted SEM using Lavaan on R with a measurement model, regressions, and categorical predictors. To improve model fit, I did item parceling. When I run this model, I run into an issue with no positive definite. When running a previous model (not the one from the previous point) using missing = FIML when I […]

I need to performe a Random Intercept Item Factor Analysis (RIIFA) but I don’t if there is a library or a function dedicated to this type of factor analysis