Detecting influence is an important diagnostic stage in every statistical analysis. This paper examines the local influence of minor perturbations of the model and data for the two-parameter logistic item response model for binary data. By applying Cook's approach in the corresponding EM algorithm used to obtain the maximum likelihood estimate of the model parameters, the normal curvature and the conformal normal curvature - building blocks for obtaining the diagnostic measures – are computed. The methodology is illustrated with two real examples and an artificial one.

中文翻译：

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2PL IRT模型对二元响应的局部影响分析

在每个统计分析中，检测影响都是重要的诊断阶段。本文研究了二进制数据的两参数对数项响应模型的模型和数据的微小扰动的局部影响。通过在相应的EM算法中使用Cook的方法来获得模型参数的最大似然估计，可以计算出法向曲率和共形法向曲率（用于获得诊断措施的构件）。用两个真实的例子和一个人工的例子来说明该方法。