Studies that focus on measurement invariance are of significant importance in proving the validation of high-stake tests, and in order to provide fairness from the results of these exams for special needs students. The aim of this study is to examine the measurement invariance of the “Central Examination for Secondary Education Institutions” in Turkey according to participant disability status. A focus group comprised of 369 visually impaired students was formed. An equal number of non-visually impaired peers were randomly selected as a reference group. Mantel-Haenszel, logistic regression, Breslow-Day, and standardization methods of classical test theory were used in order to detect items with differential item functioning (DIF). DIF analysis results proved that 16 (17.78%) of the 90 test items indicated DIF, and that ten of the DIF detected items (62.5%) represented a disadvantage for visually impaired participants. A total of 17 experts were consulted in order to investigate item bias. As a result of the collective expert opinion, five items were found to be “biased” in the Turkish ( n = 1), English ( n = 2), and in Science ( n = 2) subtests. Close agreement was obtained between the experts that the “biased items” favored non-visually impaired participants. Use of visuals/graphics, complex/lengthy texts and response options, the need for rereading questions, and the negative attitudes of readers/coders were pointed out as sources of item bias.

中文翻译：

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为视障学生评估土耳其“中等教育机构中央考试”的测量不变性

关注测量不变性的研究对于证明高风险测试的有效性以及为特殊需求学生提供这些考试结果的公平性具有重要意义。本研究的目的是根据参与者的残疾状况检查土耳其“中等教育机构中央考试”的测量不变性。一个由 369 名视障学生组成的焦点小组成立了。随机选择相同数量的非视力受损同龄人作为参考组。使用 Mantel-Haenszel、逻辑回归、Breslow-Day 和经典测试理论的标准化方法来检测具有差异项目功能 (DIF) 的项目。DIF分析结果证明，90个测试项目中有16个（17.78%）显示DIF，并且 DIF 检测到的项目中有 10 个（62.5%）对视障参与者不利。为了调查项目偏差，共咨询了 17 位专家。作为集体专家意见的结果，土耳其语 (n = 1)、英语 (n = 2) 和科学 (n = 2) 子测试中有五个项目被发现“有偏见”。专家们达成了一致意见，即“有偏见的项目”有利于无视力障碍的参与者。视觉/图形的使用、复杂/冗长的文本和响应选项、重读问题的需要以及读者/编码员的消极态度被指出是项目偏差的来源。在土耳其语 (n = 1)、英语 (n = 2) 和科学 (n = 2) 子测试中，有五个项目被发现“有偏见”。专家们达成了一致意见，即“有偏见的项目”有利于无视力障碍的参与者。视觉/图形的使用、复杂/冗长的文本和响应选项、重读问题的需要以及读者/编码员的消极态度被指出是项目偏差的来源。在土耳其语 (n = 1)、英语 (n = 2) 和科学 (n = 2) 子测试中，有五个项目被发现“有偏见”。专家们达成了一致意见，即“有偏见的项目”有利于无视力障碍的参与者。视觉/图形的使用、复杂/冗长的文本和响应选项、重读问题的需要以及读者/编码员的消极态度被指出是项目偏差的来源。