In PIAAC, skills are a latent variable that is estimated using item-response-theory models (see OECD 2013 for details).
The national population parameters are estimated using item parameters anchored at their international location, and conditioning variables are derived from the national principal components analysis and from Step 1. Step 5: Five vectors of plausible values are drawn using the method described above.
Symptoms of obstructive sleep apnea (OSA) were estimated using three items from the Karolinska Sleep Questionnaire [ 23].
In a study on physical frailty in hospitalized older people, engagement in PA was even estimated using proxy items that reflect rather functional and physical capacities than real PA [ 70, 71].
First, within each cohort there is increased measurement reliability, because when multiple inventories have been administered to the same individual, scores can be estimated using the items from all relevant inventories.
Person scores (measured in logits) are then estimated using these item subsets, and after scale equating, scores from the two item subsets can be compared using paired t-tests with a consideration of the standard error of measurement for each score.
Measurement invariance of the scale among the different subgroups (by gender and race) was estimated using differential item functioning in the IRT model.
For the β-CUSUM algorithm to be operational again, a training phase must be applied with a new training set, since the previously found confidence intervals of the β distribution are estimated using past data items.
Option characteristic curves were estimated using a nonparametric item response model to examine the probability of endorsing each of 7 options within each of 30 PANSS items as a function of standardized, overall symptom severity.
Psychiatric disorder was estimated using the 12-item General Health Questionnaire.
