Pearson product–moment correlation coefficient between item g and test score X, known as item–test or item–total correlation (Rit), and item–rest correlation (Rir) are two of the most used classical estimators for item discrimination power (IDP). Both Rit and Rir underestimate IDP caused by the mismatch of the scales of the item and the score. Underestimation of IDP may be drastic when the difficulty level of the item is extreme. Based on a simulation, in a binary dataset, a good alternative for Rit and Rir could be the Somers’ D: it reaches the ultimate values +1 and –1, it underestimates IDP remarkably less than Rit and Rir, and, being a robust statistic, it is more stable against the changes in the data structure. Somers’ D has, however, one major disadvantage in a polytomous case: it tends to underestimate the magnitude of the association of item and score more than Rit does when the item scale has four categories or more.

The field of studies in metacognition points to some limitations in the way the construct has traditionally been measured and shows a near absence of performance-based tests. The Meta-Text is a performance-based test recently created to assess components of cognition regulation: planning, monitoring, and judgment. This study presents the first evidence on the structural validity of the Meta-Text, by analyzing its dimensionality and reliability in a sample of 655 Honduran university students. Different models were tested, via item confirmatory factor analysis. The results indicated that the specific factors of planning and monitoring do not hold empirically. The bifactor model containing the general cognition regulation factor and the judgment-specific factor was evaluated as the best model (CFI = .992; NFI = .963; TLI = .991; RMSEA = .021). The reliability of the factors in this model proved to be acceptable (Ω = .701 & .699). The judgment items were well loaded only by the judgment factor, suggesting that the judgment construct may actually be another component of the metacognitive knowledge dimension but having little role in cognition regulation. The results show initial evidence on the structural validity of the Meta-Text and give rise to information previously unidentified by the field which has conceptual implications for theorizing metacognitive components.

Curiosity is one of the most important characters for elementary school students. However, the facts in the field show that the measurement model used by the teacher to identify the student's curiosity is not yet available in a standardized manner. This study aims to develop a model for measuring the curiosity of elementary school students using the graded response model (GRM) approach. This research uses quantitative method with descriptive type. The research sample used was 236 elementary school students who were randomly selected. Data were collected using a questionnaire of 16 statement items using a Likert scale approach. The data were analyzed using the response item theory approach with the GRM. The results showed that the model for measuring student curiosity in elementary schools had good location parameters, a good discriminant index, a fairly good information function with a small estimation error. The curiosity measurement model in this study can be used as an alternative for teachers to identify students' curiosity in elementary schools.