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Tests administered in studies of student achievement often have a certain amount of not-reached items (NRIs). The propensity for NRIs may depend on the proficiency measured by the test and on additional covariates. This article proposes a semiparametric model to study such relationships. Our model extends Glas and Pimentel's item response theory model for NRIs by (1) including a semiparametric representation of the distribution of the onset of NRIs, (2) modeling the relationships of NRIs with proficiency via a flexible multinomial logit regression, and (3) including additional covariates to predict NRIs. We show that Glas and Pimentel's and our model have close connections to event history analysis, thereby making it possible to apply tools developed in this context to the analysis of NRIs. Our model was applied to a timed low-stakes test of mathematics achievement. Our model fitted the data better than Glas and Pimentel's model, and allowed for a more fine-grained assessment of the onset of NRIs. The results of a simulation study showed that our model accurately recovered the relationships of proficiency and covariates with the onset of NRIs, and reduced bias in the estimates of item parameters, proficiency distributions, and covariate effects on proficiency.

Instructional language programs in German childcare centers have shown limited effectiveness. Two reasons may be that (a) the training is unconnected with everyday situations in which children typically acquire language and (b) the programs adopt a cultural model of psychological autonomy, a model that may be inconsistent with some children's background. In the present study, we implemented an everyday-based language intervention in four German childcare centers. In a prepost design, teachers (N = 37, M = 32.97 years) were first trained to adopt an elaborative, socially oriented style. Their language behavior, videotaped and analyzed during daily routines over 1 year, demonstrated significant changes (e.g., asking more open-ended questions, referring to social content and decontextualized content more often). Independent of their families' cultural orientation. children's (N = 85, M = 3.42 years) language competencies significantly increased beyond age-related development norms. In comparison with a control group of children who visited childcare centers implementing instructional language programs, children of the intervention group performed significantly better in nonword repetition (an indicator of lexical knowledge) after 1 year. The results demonstrate that, in a brief intervention, teachers' conversational style could be effectively changed toward promoting language development in a culture-sensitive way. Although the direct link to children's language development remains to be proven, results indicate that children with different cultural backgrounds could profit from this everyday-based approach without using extra settings, materials, or instructions. [ABSTRACT FROM AUTHOR]