In comparing between types of tasks, we notice that the more challenging open-ended tasks benefit significantly more than constrained item types by the use of DNN-HMMs.
Besides item PF8 and I1 (as seen in model 1), in model 2 we also constrained item A1 to 0.05, because of a negative residual variance.
Metric and Scalar models incrementally constrain item factor loadings and response category thresholds between groups.
If metric invariance was indicated we then tested for scalar invariance by also constraining item intercepts to be equal [ 24- 26].
Strong invariance (model three) involved constraining item intercepts to equality across groups (or time) to evaluate potential for systematic bias in responses from one group to another (or from one time point to another).
This analysis provides reassurance that the promotion of the items to interval measurement assumptions did not deviate from the pattern of factor coefficients compared with a less constrained distributional item profile.
Second, a grammatically appropriate two-word description (which may be true or false) is selected from a set constrained to the item or category in question: for example, a human trait ("read books"), a non-living-object trait ("don't breathe") or a specific trait ("design buildings", "aren't sharp", "is jazz").
Likelihood ratio tests between fitted nested IRT models were performed comparing the Rasch model (all item discriminations constrained to one), the one-parameter model (1PL; item discriminations are the same but freely estimated), and the two-parameter model (2PL).
Participants' open-ended responses when invited to specify further items of importance to decision-making about birth facility were also elicited to ensure study findings were not constrained by the information items listed in the survey, and these are also described.
