Browsing by Author "Luecht, Richard M."

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    Correlated effects in generalizability studies
    (1992) Smith, Philip L.; Luecht, Richard M.
    The analytical model typically used to perform generalizability analysis assumes that design effects are uncorrelated. Often, the assessment of behavioral data involves designs that employ multiple occasions or repeated trials (as in many observational and rating studies). In these cases, design effects may be serially correlated. The implications of serially correlated effects on the results of generalizability analyses are discussed. Simulated data are provided that demonstrate the biases that serially correlated effects introduce into the results. Index terms: correlated effects, estimation of variance components, generalizability theory, observational studies, repeated trials, serial correlation.
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    Item selection using an average growth approximation of target information functions
    (1992) Luecht, Richard M.; Hirsch, Thomas M.
    The derivations of several item selection algorithms for use in fitting test items to target information functions (IFS) are described. These algorithms circumvent iterative solutions by using the criteria of moving averages of the distance to a target IF and by simultaneously considering an entire range of ability points used to condition the IFS. The algorithms were tested by generating six forms of an ACT math test, each fit to an existing target test, including content-designated item subsets. The results indicate that the algorithms provided reliable fit to the target in terms of item parameters, test information functions, and expected score distributions. Index terms: computerized testing, information functions, item information, parallel tests, test construction, test information.
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    Multidimensional computerized adaptive testing in a certification or licensure context
    (1996) Luecht, Richard M.
    Multidimensional item response theory (MIRT) computerized adaptive testing, building on recent work by Segall (1996), is applied in a licensing/certification context. An example of a medical licensure test is used to demonstrate situations in which complex, integrated content must be balanced at the total test level for validity reasons, but items assigned to reportable subscore categories may be used under a MIRT adaptive paradigm to improve the reliability of the subscores. A heuristic optimization framework is outlined that generalizes to both univariate and multivariate statistical objective functions, with additional systems of constraints included to manage the content balancing or other test specifications on adaptively constructed test forms. Simulation results suggested that a multivariate treatment of the problem, although complicating somewhat the objective function used and the estimation of traits, nonetheless produces advantages from a psychometric perspective. Index terms: adaptive testing, computerized adaptive testing, information functions, licensure testing, multidimensional item response theory, sequential testing.