RQ1: Long-Term Effectiveness of Online Self-help Training in Reducing FCR and PD
PD
When testing the assumption of longitudinal measurement invariance for FCR, the multi-group univariate second order latent growth model indicated no differences between the loadings of the five longitudinal factors across time, based on the chi-square difference test comparing sub-models 0a and 1a (Latent Growth Models Supporting Research Questions 1 and 2, Increasing in Complexity






For PD, the results were similar (For FCR, the RMSEA fit index was slightly higher than the recommended criterion of .06, and for PD the RMSEA fit index was around .06, suggesting an almost adequate fit of these models to the data. The CFI and TLI suggested a somewhat poor fit of the FCR models to the data. The TLI suggested an almost adequate fit and the CFI indicated a good fit for the PD models. Both AIC and BIC suggest a better fit for the models including equal intercepts of individual items across time (2a and 2b) and for the models including equal latent slopes in the intervention and CAU group (4a and 4b). Answering the first research question (difference between the groups in effect of FCR and PD over time), this corroborates the findings mentioned above that long-term effects did not differ between the intervention group and the CAU group over time, for both FCR and PD models. In other words: the self-help was not effective in reducing FCR and PD in the intervention group long-term.