How Arithmetic Problem-Solving Strategy Sophistication Evolves Over Time in a Kindergarten Sample

To date, few studies treat problem-solving strategies as the primary outcome of interest. Yet, greater strategy sophistication predicts concurrent and future achievement, as well as deeper conceptual understanding, motivating closer examination. The purpose of this study is to describe how modal arithmetic strategy sophistication evolves over the course of a teaching experiment in a kindergarten classroom in the Mountain West. We developed a system to code arithmetic performance for three timescales (between sessions, time within-session, and attempt to solve) across nine story problem structures. We show that modal strategy sophistication varies with the location of the unknown quantity within story structures and increases across sessions and successive attempts to solve a story-problem. Implications for teaching and learning are discussed.