Social inequality in mathematical skill is apparent at kindergarten entry and persists during elementary school. To level the playing field, we trained teachers to assess children’s numerical and spatial skills every 10 wk. Each assessment provided teachers with information about a child’s growth trajectory on each skill, information designed to help them evaluate their students' progress, reflect on past instruction, and strategize for the next phase of instruction. A key constraint is that teachers have limited time to assess individual students. To maximize the information provided by an assessment, we adapted the difficulty of each assessment based on each child’s age and accumulated evidence about the child’s skills. Children in classrooms of 24 trained teachers scored 0.29 SD higher on numerical skills at posttest than children in 25 randomly assigned control classrooms (P = 0.005). We observed no effect on spatial skills. The intervention also positively influenced children’s verbal comprehension skills (0.28 SD higher at posttest, P < 0.001), but did not affect their print-literacy skills. We consider the potential contribution of this approach, in combination with similar regimes of assessment and instruction in elementary schools, to the reduction of social inequality in numerical skill and discuss possible explanations for the absence of an effect on spatial skills.

数学技能方面的社会不平等在幼儿园入学时就很明显，并在小学期间持续存在。为了创造公平的竞争环境，我们培训教师每 10 周评估孩子们的数字和空间技能。每次评估都为教师提供了有关孩子每项技能的成长轨迹的信息，这些信息旨在帮助他们评估学生的进步，反思过去的教学，并为下一阶段的教学制定策略。一个关键的限制是教师评估个别学生的时间有限。为了最大限度地利用评估提供的信息，我们根据每个孩子的年龄和积累的有关孩子技能的证据调整了每次评估的难度。24 名受过培训的教师所在的教室中的孩子在后测中的数字技能得分比 25 个随机分配的对照教室中的孩子高出 0.29 SD（P = 0.005）。我们观察到对空间技能没有影响。干预措施还对儿童的言语理解能力产生了积极影响（后测时提高了 0.28 SD，P < 0.001），但不影响他们的印刷体读写能力。我们考虑了这种方法与小学中类似的评估和教学制度相结合对减少数字技能方面的社会不平等的潜在贡献，并讨论了对空间技能没有影响的可能解释。