Comparing set-to-number and number-to-set measures of cardinal number knowledge in preschool children using latent variable modeling

Children's understanding of the cardinal numbers before entering school provides the foundation for formal mathematics learning. Two types of tasks have been primarily used to measure children's knowledge of cardinal numbers: set-to-number and number-to-set tasks. However, there has been a continued debate as to whether the two types of tasks measure the same conceptual construct, allowing comparison and interchangeable use, or whether they measure different but related constructs. To answer this question, we analyzed the relation between task and item level performance on representative set-to-number (e.g., How-Many?) and number-to-set (Give-N) tasks in a large group of 3- to 4-year-old preschoolers (N = 204, median age = 3y 10 m). By constructing and comparing models with different latent variable structures, we found that the best-fitting model was a bi-factor model, where performance on set-to-number and number-to-set tasks is best explained by both overlapping and some distinct aspects of cardinal number knowledge. Further analyses ruled out the idea that differences between tasks were due solely to non-numerical, general cognitive or language factors. Together these results suggest that set-to-number and number-to-set tasks have some commonalities but also retain at least some significant conceptual distinctness. Based on these results, we suggest these two types of tasks should no longer be used indiscriminately to inform theory or educational assessment of numerical abilities in preschool children.