Webbink Dinand, Hay David, Visscher Peter M
CPB Netherlands Bureau for Economic Policy Analysis, The Hague, the Netherlands.
Twin Res Hum Genet. 2007 Aug;10(4):573-80. doi: 10.1375/twin.10.4.573.
This article analyzes the effect of classroom separation of twins on their cognitive abilities, measured at different ages in Dutch primary education. We use a large longitudinal school-based sample of twins and their classmates. The analysis tries to reduce the bias by unobserved factors due to the nonrandom assignment of twins by taking into account differences in school environment, previous test scores and variation in class assignment between years. We find that classroom separation matters for language in Grade 2. Nonseparated twins score higher on language, and the difference is larger for same-sex pairs. This finding is robust for various methods that take unobserved effects into account. In addition, there is some evidence for higher scores in arithmetic in Grade 2. For the higher grades we find no effect of classroom separation on cognitive ability. In the analysis of the effect of a separation of at least 3 years we find that separation increases language performance between Grade 6 and 8 for opposite-sex pairs.
本文分析了荷兰小学教育中不同年龄段双胞胎的课堂分离对其认知能力的影响。我们使用了一个基于学校的大型双胞胎及其同学的纵向样本。该分析试图通过考虑学校环境差异、先前的考试成绩以及各年份班级分配的变化，来减少因双胞胎非随机分配而导致的未观察因素的偏差。我们发现，课堂分离对二年级的语言能力有影响。未分离的双胞胎在语言方面得分更高，同性双胞胎的差异更大。这一发现对于各种考虑未观察效应的方法来说是稳健的。此外，有一些证据表明二年级的算术成绩更高。对于高年级，我们发现课堂分离对认知能力没有影响。在对至少3年分离影响的分析中，我们发现异性双胞胎在六年级到八年级之间的分离会提高语言表现。
