The 2015 Trends in International Mathematics and Science Study (TIMSS) involved 57 countries and 43 different languages to assess students’ achievement in mathematics and science. The purpose of this study is to evaluate whether items and test scores are affected as the differences between language families and cultures increase. Using differential item functioning (DIF) procedures, we compared the consistency of students’ performance across three combinations of languages and countries: (a) same language but different countries, (b) same countries but different languages, and (c) different languages and different countries. The analyses consisted of the detection of the number of DIF items for all paired comparisons within each condition, the direction of DIF, the magnitude of DIF, and the differences between test characteristic curves. As the countries were more distant with respect to cultures and language families, the presence of DIF increased. The magnitude of DIF was greatest when both language and country differed, and smallest when the languages were same, but the countries were different. Results suggest that when TIMSS results are compared across countries, the language- and country-specific differences which could reflect cultural, curriculum, or other differences should be considered.

2015年国际数学和科学研究趋势（TIMSS）涉及57个国家和43种不同的语言，以评估学生在数学和科学方面的成绩。这项研究的目的是评估随着语言族群和文化之间差异的增加，项目和测验分数是否会受到影响。我们使用差异项功能（DIF）程序，比较了学生在三种语言和国家/地区组合中的学习效果的一致性：（a）同一语言但不同的国家，（b）同一国家但不同的语言，以及（c）不同的语言和不同的国家。分析包括检测每种条件下所有成对比较的DIF项数，DIF的方向，DIF的大小以及测试特性曲线之间的差异。随着这些国家在文化和语言族裔方面的距离越来越远，DIF的存在也有所增加。当语言和国家/地区不同时，DIF的大小最大，当语言相同但国家/地区不同时，DIF的大小最小。结果表明，在比较各国的TIMSS结果时，应考虑可能反映文化，课程或其他差异的特定语言和特定国家的差异。