Arnold Manuel, Voelkle Manuel C, Brandmaier Andreas M
Psychological Research Methods, Department of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany.
Max Planck UCL Centre for Computational Psychiatry and Ageing Research, Berlin, Germany.
Front Psychol. 2021 Jan 28;11:564403. doi: 10.3389/fpsyg.2020.564403. eCollection 2020.
Structural equation model (SEM) trees are data-driven tools for finding variables that predict group differences in SEM parameters. SEM trees build upon the decision tree paradigm by growing tree structures that divide a data set recursively into homogeneous subsets. In past research, SEM trees have been estimated predominantly with the R package semtree. The original algorithm in the semtree package selects split variables among covariates by calculating a likelihood ratio for each possible split of each covariate. Obtaining these likelihood ratios is computationally demanding. As a remedy, we propose to guide the construction of SEM trees by a family of score-based tests that have recently been popularized in psychometrics (Merkle and Zeileis, 2013; Merkle et al., 2014). These score-based tests monitor fluctuations in case-wise derivatives of the likelihood function to detect parameter differences between groups. Compared to the likelihood-ratio approach, score-based tests are computationally efficient because they do not require refitting the model for every possible split. In this paper, we introduce score-guided SEM trees, implement them in semtree, and evaluate their performance by means of a Monte Carlo simulation.
结构方程模型(SEM)树是一种数据驱动工具,用于寻找能够预测SEM参数中组间差异的变量。SEM树基于决策树范式构建,通过生长树结构将数据集递归划分为同质子集。在过去的研究中,SEM树主要使用R包semtree进行估计。semtree包中的原始算法通过计算每个协变量的每个可能分割的似然比,在协变量中选择分割变量。获取这些似然比的计算量很大。作为一种补救措施,我们建议通过最近在心理测量学中流行的一类基于分数的检验来指导SEM树的构建(Merkle和Zeileis,2013;Merkle等人,2014)。这些基于分数的检验监测似然函数的逐案导数的波动,以检测组间的参数差异。与似然比方法相比,基于分数的检验计算效率更高,因为它们不需要为每个可能的分割重新拟合模型。在本文中,我们介绍了分数引导的SEM树,在semtree中实现了它们,并通过蒙特卡罗模拟评估了它们的性能。