International large-scale assessments like international computer and information literacy study (ICILS) (Fraillon et al. in International Association for the Evaluation of Educational Achievement (IEA), 2015) provide important empirically-based knowledge through the proficiency scales, of what characterizes tasks at different difficulty levels, and what that says about students at different ability levels. In international comparisons, one of the threats against validity is country differential item functioning (DIF), also called item-by-country interaction. DIF is a measure of how much harder or easier an item is for a respondent of a given group as compared to respondents from other groups of equal ability. If students from one country find a specific item much harder or easier than students from other countries, it can impair the comparison of countries. Therefore, great efforts are directed towards analyzing for DIF and removing or changing items that show DIF. From another angle, however, this phenomenon can be seen not only as a threat to validity, but also as an insight into what distinguishes students from different countries, and possibly their education, on a content level, providing even more pedagogically useful information. Therefore, in this paper, the data from ICILS 2013 is re-analyzed to address the research question: Which kinds of tasks do Danish, Norwegian, and German students find difficult and/or easy in comparison with students of equal ability from other countries participating in ICILS 2013? The analyses show that Norwegian and Danish students find items related to computer literacy easier than their peers from other countries. On the other hand, Danish and, to a certain degree, Norwegian students find items related to information literacy more difficult. Opposed to this, German students do not find computer literacy easier, but they do seem to be comparably better at designing and laying out posters, web pages etc. This paper shows that essential results can be identified by comparing the distribution of difficulties of items in international large-scale assessments. This is a more constructive approach to the challenge of DIF, but it does not eliminate the serious threat to the validity of the comparison of countries.

中文翻译：

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DIF作为教学工具：对ICILS中的项目特征进行分析，以了解学生正在努力学习的内容

国际大规模评估，例如国际计算机和信息素养研究（ICILS）（国际教育成就评估协会（IEA），Fraillon等人，2015年），通过熟练程度量表，提供了基于经验的重要知识，这些知识是任务的特征处于不同的难度水平，这说明了不同能力水平的学生。在国际比较中，有效性的威胁之一是国家差异项功能（DIF），也称为逐项交互。DIF衡量的是与同等能力的其他组的受访者相比，某项对于给定组的受访者而言难易得多。如果一个国家的学生比其他国家的学生更难或更容易找到特定的项目，它会损害国家之间的比较。因此，将大量精力用于分析DIF并删除或更改显示DIF的项目。但是，从另一个角度来看，这种现象不仅可以看作是对有效性的威胁，而且还可以看作是对区别于不同国家的学生（以及他们的受教育程度）的理解，从内容的层面上讲，提供了更具教学意义的有用信息。因此，在本文中，将对来自ICILS 2013的数据进行重新分析，以解决以下研究问题：与来自其他国家/地区的同等能力的学生相比，丹麦，挪威和德国的学生感到哪些困难和/或容易？在ICILS 2013中？分析表明，挪威和丹麦的学生比其他国家的同伴更容易找到与计算机素养相关的项目。另一方面，丹麦学生和一定程度上是挪威学生发现与信息素养相关的项目更加困难。与此相反，德国学生并没有发现计算机知识的普及，但是他们在设计和布置海报，网页等方面似乎要好得多。本文表明，通过比较项目中困难的分布可以确定基本结果。国际大规模评估。这是应对DIF挑战的一种更具建设性的方法，但并不能消除对国家比较有效性的严重威胁。但是它们似乎在设计和布置海报，网页等方面确实要好得多。本文表明，可以通过比较国际大规模评估中项目难度的分布来确定基本结果。这是应对DIF挑战的一种更具建设性的方法，但并不能消除对国家比较有效性的严重威胁。但是它们似乎在设计和布置海报，网页等方面确实要好得多。本文表明，可以通过比较国际大规模评估中项目难度的分布来确定基本结果。这是应对DIF挑战的一种更具建设性的方法，但并不能消除对国家比较有效性的严重威胁。