Hybrid Measurement Models for Technology-Enhanced Assessments Through mIRT-bayes

Abstract

Technology-enhanced assessments (TEAs) are rapidly emerging in educational measurement. In contexts such as simulation and gaming, a common challenge is handling complex streams of information, for which new statistical innovations are needed that can provide high quality proficiency estimates for the psychometrics of complex TEAs. Often in educational assessments with formal measurement models, latent variable models such as item response theory (IRT) are used to generate proficiency estimates from evidence elicited. Such robust techniques have become a foundation of educational assessment, when models fit. Another less common approach to compile evidence is through Bayesian networks, which represent a set of random variables and their conditional dependencies via a directed acyclic graph. Network approaches can be much more flexibly designed for complex assessment tasks and are often preferred by task developers, for technology-enhanced settings. However, the Bayesian network-based statistical models often are difficult to validate and to gauge the stability and accuracy, since the models make assumptions regarding conditional dependencies that are difficult to test. Here a new measurement model family, mIRT-bayes, is proposed to gain advantages of both latent variable models and network techniques combined through hybridization. Specifically, the technique described here embeds small Bayesian networks within an overarching multidimensional IRT model (mIRT), preserving the flexibility for task design while retaining the robust statistical properties of latent variable methods. Applied to simulation-based data from Harvard's Virtual Performance Assessments (VPA), the results of the new model show acceptable fit for the overarching mIRT model, along with reduction of the standard error of measurement through the embedded Bayesian networks, compared to use of mIRT alone. Overall for respondents, a finer grain-size of inference is made possible without additiona testing time or scoring resources, showing potentially promise for this family of new hybrid models.