The proportion of missing values in those items which were used in our analysis was below 0.3%, except for income with 12.7% missings.
Factor one consisted of the GÜF items which were not associated with the screening items as indicated by t-contrasts and F-tests except for item 10 (anger about loud sounds).
Coding "not applicable" as "no" would have had the following potential consequence: e.g. if a participant is willing to disclose the whole data-set except one item which is not applicable to his context, he would have been falsely categorized as completely reluctant (i.e. "0" in regression analysis).
When comparing the means in the second part of the t-test, it was clear that most of the items supported the null hypothesis (sig. > .05) as there were no differences in means between the two groups, except for one item which is education (.018).018
Answers were rated on a four-point response scale, except for the global QoL item, which was assessed on a seven-point scale.
Using the guidelines provided by Millsap and Yun-Tein [ 22], we began by fitting a model in which all parameters (except the loading of the first item, which was set equal to 1 for model identification purposes) were freely estimated across studies (configural invariance).
All values except item 23 (which was below the criterion of 0.5) significantly loaded onto the seven latent factors, ranging from 0.51 to 0.883.
The difference between the estimates was not statistically significant in both approaches and for all evaluated items, except for age, which was statistically significant in the evaluation of subgroups from individual studies and not statistically significant in the sensitivity analysis (Table 7).
Similar to our analysis, they used OLS regression modelling, using all individual MSWS-12 item scores (except for item 11, which was removed due to collinearity) to provide the best performing equation (MAE=0.148, RMSE=0.198 and adjusted R=0.361).
All the items in the FACT-G had item-subscale correlations higher than 0.50 except for item E2 which was 0.34.
All items had factor loadings above 0.60 except for item 25, which was 0.46.
