Xcalibre 边缘最大概似估计法

Xcalibre 4在对评估数据进行项目反应理论(IRT)分析的软件中居于领先地位。Xcalibre 4使用4个二分(dichotomous)和5个多分类(polytomous) IRT模型来调整您的检验,并可以产生专业汇总分析报告,包括内嵌图形和表格来帮助数据解释。Xcalibre 4是目前最综合的IRT软件,完全不需要执行DOS命令!

XCALIBRE - Marginal Maximum-Likelihood Estimation
XCALIBRE represents an improved approach to the challenge of IRT item parameter estimation. A significant amount of attention has been directed at marginal maximum-likelihood estimation methods for obtaining IRT parameter estimates. Accurate estimation of IRT item parameters using maximum-likelihood approaches, including Bayesian techniques, tend to require longer tests and larger sample sizes. A generally accepted guideline for obtaining reasonable item parameter estimates with maximum-likelihood techniques is at least 50 items and 1,000 examinees (for a 3-parameter IRT model). Using marginal maximum-likelihood estimation, XCALIBRE can provide accurate item parameter estimates with fewer examinees and shorter tests.

Features
Able to estimate both 2- and 3-parameter IRT item parameters;
Works with very large data sets;
Floating priors: XCALIBRE implements Bayesian prior distributions on the individual item parameters, but these prior distributions may be allowed to be updated during the estimation process; "Fixing" items: Common (anchor) items in a larger data set may be "fixed" to specified parameter values (from a previous estimation run). Fixing selected item parameters results in automatic linking of the remaining item parameters onto the target (common) scale; Evaluation of the fit of each item to the IRT model is provided; and
Works with incomplete data sets and can differentiate between items that are omitted and those that were not attempted.

Review of XCALIBRE
Read the review of XCALIBRE which was published in the journal Applied Psychological Measurement, Vol. 20, No. 3, September 1996, pp. 303-307. Reprinted by permission.

Specifications
XCALIBRE can analyze up to 750 items with no limit on the number of examinees.

System Requirements
Windows 95, 98, NT, ME, 2000, XP

Test Analysis Package
XCALIBRE is also available as part of the Item and Test Analysis Package.

Books about Item Response Theory and Related Methods:
Applications of Item Response Theory to Practical Testing Problems
Essays on Item Response Theory
Explanatory Item Response Models
Fundamentals of Item Response Theory
Handbook of Modern Item Response Theory
Item Response Theory for Psychologists
Item Response Theory: Parameter Estimation Techniques
Item Response Theory: Principles and Applications
Test Scoring
The EM Algorithm and Related Statistical Models