Finch Holmes, Edwards Julianne M
Ball State University, Muncie, IN, USA.
Educ Psychol Meas. 2016 Aug;76(4):662-684. doi: 10.1177/0013164415608418. Epub 2015 Oct 12.
Standard approaches for estimating item response theory (IRT) model parameters generally work under the assumption that the latent trait being measured by a set of items follows the normal distribution. Estimation of IRT parameters in the presence of nonnormal latent traits has been shown to generate biased person and item parameter estimates. A number of methods, including Ramsay curve item response theory, have been developed to reduce such bias, and have been shown to work well for relatively large samples and long assessments. An alternative approach to the nonnormal latent trait and IRT parameter estimation problem, nonparametric Bayesian estimation approach, has recently been introduced into the literature. Very early work with this method has shown that it could be an excellent option for use when fitting the Rasch model when assumptions cannot be made about the distribution of the model parameters. The current simulation study was designed to extend research in this area by expanding the simulation conditions under which it is examined and to compare the nonparametric Bayesian estimation approach to the Ramsay curve item response theory, marginal maximum likelihood, maximum a posteriori, and the Bayesian Markov chain Monte Carlo estimation method. Results of the current study support that the nonparametric Bayesian estimation approach may be a preferred option when fitting a Rasch model in the presence of nonnormal latent traits and item difficulties, as it proved to be most accurate in virtually all scenarios that were simulated in this study.
估计项目反应理论(IRT)模型参数的标准方法通常在一组项目所测量的潜在特质服从正态分布的假设下进行。在存在非正态潜在特质的情况下估计IRT参数已被证明会产生有偏差的个体和项目参数估计值。已经开发了许多方法,包括拉姆齐曲线项目反应理论,以减少这种偏差,并且已证明这些方法在相对大的样本和长评估中效果良好。非正态潜在特质和IRT参数估计问题的另一种方法,即非参数贝叶斯估计方法,最近已被引入文献。对该方法的早期研究表明,当在无法对模型参数分布做出假设的情况下拟合拉施模型时,它可能是一个很好的选择。当前的模拟研究旨在通过扩展研究的模拟条件来扩展该领域的研究,并将非参数贝叶斯估计方法与拉姆齐曲线项目反应理论、边际最大似然法、最大后验法以及贝叶斯马尔可夫链蒙特卡罗估计方法进行比较。当前研究的结果支持,在存在非正态潜在特质和项目难度的情况下拟合拉施模型时,非参数贝叶斯估计方法可能是一个更优的选择,因为在本研究模拟的几乎所有场景中,它都被证明是最准确的。