Approach to analysing correlated contextual factors: an application for studies on violence.
Approach to analysing correlated contextual factors: an application for studies on violence.
复制标题
分析相关背景因素的方法：暴力研究的应用。
DOI：
10.1136/injuryprev-2020-043967
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Cavanaugh,JosephE
中科院分区：
文献类型：
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作者：
Ramirez,MarizenR;Flores,JavierE;Cheng,Gang;Peek-Asa,Corinne;Cavanaugh,JosephE
背景许多公共卫生研究，特别是在暴力领域，研究了背景或群体水平因素对健康结果的影响。通常，这些背景因素表现出很强的成对相关性，当这些因素作为协变量包含在统计模型中时，这构成了挑战。这种模型的特点可能是膨胀的标准误差和不稳定的参数估计，可能会大幅波动，从样本到样本，其中过度的估计变异性是由膨胀的标准误差反映。MethodsWe提出了一个三阶段的方法来分析相关的上下文因素，进行如下：（1）对相关变量的原始集合执行主成分分析（PCA），（2）初级生成的主成分被包括在多水平多变量模型中，以及（3）这些分量的估计参数被变换为每个原始上下文因素的估计。使用校园暴力的数据，我们研究了学校犯罪和相关的上下文学校因素（即，英语水平，学习成绩，学生与教师的比例，平均班级规模和儿童免费和减少膳食）之间的关联。当模型与主成分拟合，学校犯罪被发现是正相关的学校的学生与教师的比例，平均教室大小和学习成绩，但负相关的儿童的比例谁是免费的，减少mean.ConclusionOur多步骤的方法是一种方法来解决多重共线性暴力的社会流行病学研究中遇到的。
BackgroundNumerous public health studies, especially in the area of violence, examine the effects of contextual or group-level factors on health outcomes. Often, these contextual factors exhibit strong pairwise correlations, which pose a challenge when these factors are included as covariates in a statistical model. Such models may be characterised by inflated standard errors and unstable parameter estimates that may fluctuate drastically from sample to sample, where the excessive estimation variability is reflected by inflated standard errors.MethodsWe propose a three-stage approach for analysing correlated contextual factors that proceeds as follows: (1) a principal components analysis (PCA) is performed on the original set of correlated variables, (2) the primary generated principal components are included in a multilevel multivariable model and (3) the estimated parameters for these components are transformed into estimates for each of the original contextual factors. Using school violence data, we examined the associations between school crime and correlated contextual school factors (ie, English proficiency, academic performance, pupil to teacher ratio, average class size and children on free and reduced meals).ResultsFrom models ignoring correlations, school crime was not reliably associated with any of the contextual school factors. When models were fit with principal components, school crime was found to be positively associated with a school’s student to teacher ratio, average classroom size and academic performance but negatively associated with the proportion of children who were on free and reduced meals.ConclusionOur multistep approach is one way to address multicollinearity encountered in social epidemiological studies of violence.