Frantom Catherine, Green Kathy E, Lam Tony C M
University of Missouri, Columbia 65203, USA.
J Appl Meas. 2002;3(1):38-49.
The purpose of this study was to evaluate the effects of item grouping on local independence and item invariance, the characteristics of items scaled under the Rasch model that make them sample-free. Item fit and calibration for attitude items presented in a grouped versus random order were examined. It was hypothesized that grouping items to facilitate interpretation central to a construct may result in a failure of invariance. Data were 107 responses to a 40-item mail survey of teachers' opinions about the Ontario Ministry's grade 9 literacy test. Effects of grouping and item phrasing on invariance were found. Results, however, generally support the use of grouping of items to provide a higher person separation, and potentially higher quality data.
本研究的目的是评估项目分组对局部独立性和项目不变性的影响，以及在拉施模型下进行量表化的项目所具有的使其不受样本影响的特征。对以分组形式与随机顺序呈现的态度项目的项目拟合度和校准情况进行了检验。研究假设，将项目分组以促进对某个结构核心内容的解释可能会导致不变性失效。数据来自对40个项目的邮件调查的107份回复，该调查是关于教师对安大略省教育部9年级读写能力测试的看法。研究发现了分组和项目措辞对不变性的影响。然而，结果总体上支持使用项目分组来实现更高的人员区分度，并可能获得更高质量的数据。
