This article provides an empirically grounded analysis for two fundamentally different models of mathematics teachers’ beliefs about student diversity in Russian secondary schools: exclusive and inclusive models. Although teachers’ beliefs are considered a central factor for the differentiated approach, teachers’ beliefs could be stereotyped and, consequently, the evaluation of a student’s ability would be systematically shifted and decisions about the possibility of teaching a student would be incorrect. Semi-structured interviews with 30 mathematics teachers allowed us to investigate what criteria teachers claim to employ while classifying students in the classroom and what expectations they have for each group of students. It was found that within the exclusive model, teachers have an image of a “normal” student and use discrete categories for labelling students with reference to the “normality”. Within the inclusive model, teachers tend not to match students with discrete categories; rather they prefer to compare a student only with herself or himself. Research findings are discussed in the context of a possible “fixed effect” on a student’s development. However, there is a need for further investigation of a connection between teachers’ belief systems, teaching practices and student achievement.

中文翻译：

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隐藏的差异化机制：教师对学生多样性的信念

本文提供了基于经验的分析，针对俄罗斯中学数学老师关于学生多样性的两种根本不同的模型：排他模型和全纳模型。尽管教师的信念被认为是差异化教学方法的核心因素，但是教师的信念可能会被刻板印象化，因此，对学生能力的评估将被系统地转移，并且关于教学生的可能性的决定将是不正确的。通过对30位数学老师的半结构化访谈，我们可以调查教师在对教室中的学生进行分类时声称采用的标准以及对每组学生的期望。发现在独家模型中，教师具有“正常”学生的图像，并使用离散类别来参考“正常”来标记学生。在包容性模式中，教师往往不会将学生与离散类别相匹配。他们宁愿只将学生与自己进行比较。在对学生的发展可能产生“固定影响”的情况下讨论研究发现。但是，有必要进一步研究教师的信仰体系，教学实践和学生成就之间的联系。