Length measurement in the early years: teaching and learning with learning trajectories

Measurement is a critical component of mathematics education, but research on the learning and teaching of measurement is limited. We previously introduced, refined, and validated a developmental progression–the cognitive core of a learning trajectory–for length measurement in the early years. A complete learning trajectory includes instructional activities and pedagogical strategies, correlated with each level of the developmental progression. This study evaluated a portion of our learning trajectory, focusing on the instructional component. We found that the instruction was successful in promoting a progression from one level to the next for 40% of the children, with others developing positive new behaviors (but not sufficient to progress to a new level). We identified specific characteristics of the interventions’ tasks and teacher–child interactions that engendered learning. The use of standard or multiple nonstandard units may play different roles at different points in the learning trajectory.