ABSTRACT Item stem formats can alter the cognitive complexity as well as the type of abilities required for solving mathematics items. Consequently, it is possible that item stem formats can affect the dimensional structure of mathematics assessments. This empirical study investigated the relationship between item stem format and the dimensionality of mathematics assessments. A sample of 671 sixth-grade students was given two forms of a mathematics assessment in which mathematical expression (ME) items and word problems (WP) were used to measure the same content. The effects of mathematical language and reading abilities in responding to ME and WP items were explored using unidimensional and multidimensional item response theory models. The results showed that WP and ME items appear to differ with regard to the underlying abilities required to answer these items. Hence, the multidimensional model fit the response data better than the unidimensional model. For the accurate assessment of mathematics achievement, students’ reading and mathematical language abilities should also be considered when implementing mathematics assessments with ME and WP items.

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项目词干格式对数学评估的维度结构的影响

摘要项目词干格式可以改变认知复杂性以及解决数学项目所需的能力类型。因此，项目词干格式可能会影响数学评估的维度结构。这项实证研究调查了项目词干格式与数学评估的维数之间的关系。对671名六年级学生的样本进行了两种形式的数学评估，其中数学表达式（ME）项和单词问题（WP）用来衡量相同的内容。利用一维和多维项目响应理论模型，探讨了数学语言和阅读能力对我和WP项目的响应。结果表明，WP和ME项目似乎在回答这些项目所需的基本能力方面有所不同。因此，多维模型比一维模型更适合响应数据。为了准确评估数学成绩，在使用ME和WP项目进行数学评估时，还应考虑学生的阅读和数学语言能力。