Browsing by Author "Huang, Lan"

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    Improving the Use of Subscores on a Test Battery: Some Reliability and Validity Evidence from the Wechsler Intelligence Scale for Children- Fourth Edition
    (2015-05) Huang, Lan
    It is widely believed that subscores can give us more information about an examinee. Thus they can be useful in planning instructional and remedial efforts, or making vocational or academic placement decisions. However, past research has shown that subscores are often not as useful as hoped either because they do not have high reliability or because they seem to add little information. This dissertation investigated if there is any evidence of reliability and validity of the subscores from the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV). The dissertation is composed of three separate studies using three empirical data sets. In the first study, we investigated the reliability issue of subscore differences and concluded that difference scores can be reliable. In the second study, we proposed two graphical methods to help with latent variable interpretation and the construct validation of subscores that are based on factor models. One way to use subscores is to do profile analysis. In the third study, using subscores from a special population and a profile analysis technique, we found profile patterns are useful in differentiating cases in various diagnostic categories and profile patterns actually outperformed profile levels.
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    Measuring speed of numerical reasoning.
    (2010-12) Huang, Lan
    If numerical reasoning items are administered with time limits, will two dimensions be required to account for the responses, a numerical ability dimension and a speed dimension? If we want to know how quickly a person solves a problem, how can we obtain a reliable measure of speed? This study reanalyzed the data collected by Semmes, Davison, & Close (2009) in which one hundred and eighty-one college students answered 74 numerical reasoning items. Every item was administered with and without a time limit by half of the students. Three two-dimensional models were fit to item responses under self-paced and experimenter-paced conditions and response times under self-paced administrations. The best fitting model suggested that, other than the Level dimension, a second Speed dimension was needed to account for variation in numerical reasoning performance under experimenter-paced administration. After adding response time to the model, we saw a significant increase in the reliability estimate for the Speed factor compared to prior research with the same data, but estimating speed scores using only the experimenter-paced responses (Semmes et al., 2009). The validity of the Speed dimension was supported by its unique contribution to the prediction of ACT scores after controlling for the variation accounted for by the Level dimension. An alternative method of measuring Speed is mentioned. Some previous research using response times for other purposes besides measurement of speed are also discussed.