Model Selection of Nested and Non-Nested Item Response Models Using Vuong Tests

Abstract

In this paper, we apply Vuong’s general approach of model selection to the comparison of nested and non-nested unidimensional and multidimensional item response theory (IRT) models. Vuong’s approach of model selection is useful because it allows for formal statistical tests of both nested and non-nested models. However, only the test of non-nested models has been applied in the context of IRT models to date. After summarizing the statistical theory underlying the tests, we investigate the performance of all three distinct Vuong tests in the context of IRT models using simulation studies and real data. In the non-nested case we observed that the tests can reliably distinguish between the graded response model and the generalized partial credit model. In the nested case, we observed that the tests typically perform as well as or sometimes better than the traditional likelihood ratio test. Based on these results, we argue that Vuong’s approach provides a useful set of tools for researchers and practitioners to effectively compare competing nested and non-nested IRT models.     

Omission bias and perceived intention in children and adults

Omission bias refers to the tendency to judge acts of commission as morally worse than equivalent acts of omission. Children aged 7–8 and 11–12 years, as well as adults, made moral judgements about acts of commission and omission in two conditions in which the protagonist obtained a self‐directed benefit. In the antisocial condition, the other person was harmed; in the selfish condition, the other person was not harmed. The results showed that adults and both age groups of children judged that the agent who did something (act of commission) was morally worse than the agent who did nothing (omission) for both antisocial and selfish conditions, although this judgement tendency was clearer in the selfish condition than in the antisocial condition. Agent intention was held constant across commission and omission, but most participants rated the intention of the agent who did something as stronger than that of the agent who did nothing. These results suggest that omission bias occurs regardless of differences in age and situation. In addition, perceived intention appears to change in conjunction with omission bias.     

Perceived Coparenting Support and Later Relationship Status among Cohabiting Parents

Abstract

To help with the fragile nature of cohabiting parents' relationship, more understanding about their interpersonal experiences is needed to identify factors that matters for their relationship stability. We examined how cohabiting parents' perceived coparenting support from their partner was associated with their later relationship status (married/cohabiting/not together). Further, we examined the possible moderating effect of perceived coparenting support on the association between marriage plans and later relationship status. Results suggested that the associations between fathers' plans and couples' marriage entrance as well as continued cohabitation were dependent upon fathers' perceived coparenting support from mothers. Clinical and research implications are discussed.