The effect of labeled benchmarks on number line estimations. In A. Van Hoogmoed (chair), 'The number line revisited: New insights into strategy use and training'. Symposium conducted at the biennial meeting of the European Association for Research on Learning and Instruction (EARLI)

Number line estimation (NLE) studies have shown that children can use benchmarks to position numbers on a number line (Barth & Paladino, 2011). Peeters et al. (2016) however demonstrated that the provision of additional benchmarks at 25% and 75% of the number line did not lead to better NLE performance in young children. In the present study we investigated whether labeling benchmarks (i.e. giving a numeric label to the benchmark) has an effect on children's NLE accuracy and benchmark-based strategy use, and whether this differs between grades. Eighty-three third graders and 72 sixth graders were randomly assigned to one of three conditions: (a) a control condition with labeled benchmarks at the origin (0) and endpoint (1000), (b) an unlabeled condition with additional unlabeled benchmarks at 25%, 50% and 75% of the number line, and (c) a labeled condition in which these benchmarks were labeled with, respectively, 250, 500 and 750. Findings showed that third graders estimated more accurately in the labeled condition than in the unlabeled one, while the estimation accuracy of sixth graders did not differ between these two conditions. Trial-by-trial verbal reports and model fits showed that the majority of third graders were fitted best with the four-cycle power model (i.e. using benchmarks at 25% and 75%) in the labeled condition only. Whereas the majority of sixth graders fitted best with this model in both the unlabeled and labeled condition. These findings have implications for the amount of support that should be provided to children learning NLE.status: publishe