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To date, only frequentist model-selection methods have been studied with mixed-format data in the context of IRT model-selection, and it is unknown how popular Bayesian model-selection methods such as DIC, WAIC, and LOO perform. In this study, we present the results of a comprehensive simulation study that compared the performances of eight model-selection methods with mixed-format data to select the correct combination of IRT models. Findings of the simulation study indicate that DIC, WAIC, and LOO had excellent statistical power to choose the correct IRT model combination. They performed comparably with LRT and slightly preferably than AIC, and considerably better than BIC, AICc, and SABIC. In addition, the performances of the three Bayesian methods were more stable than those of AIC and LRT regardless of the sample size and ability distribution. The eight model-selection methods were applied to a real dataset for demonstration purpose. [ABSTRACT FROM AUTHOR]

Wheat stripe rust, caused by the fungal pathogen Puccinia striiformis f. sp. tritici (Pst), is a destructive wheat disease in China. The Gansu–Ningxia region (GN) is a key area for pathogen over-summering in China, and northwestern Hubei (HB) is an important region for pathogen over-wintering, serving as a source of inoculum in spring epidemic regions. The spatiotemporal population genetic structure of Pst in HB and the pathogen population exchanges between GN and HB are important for estimating the risk of interregional epidemics. Here, 567 isolates from GN and HB were sampled from fall 2016 to spring 2018 and were genotyped using simple sequence repeat markers. The genotypic and genetic diversity of Pst subpopulations in HB varied among seasons and locations. Greater genetic diversification levels were found in the spring compared with fall populations using principal coordinate analysis and Bayesian assignments. In total, there were 17 common genotypes among the 208 determined, as shown by a small overlap of genotypes in the principal coordinate analysis and dissimilar Bayesian assignments in both regions, which revealed the limited genotype exchange between the populations of GN and HB. [ABSTRACT FROM AUTHOR]