Development and validation of a preformal test for mathematical proof competence

Proving is a core part of mathematics, prompting educators to push for earlier inclusion in curricula. Thus, an appropriate test for proof competence is needed already at the primary school level. The Preformal Proving Test (PfPT), introduced here, is an online assessment covering proof in Boolean Logic, Set Theory, and Elementary Number Theory. Designed without formal language and prior knowledge requisites, it ensures accessibility for children. We present the findings from two studies: an online pilot study ( n = 409, 42% identifying as female; M a g e = 9.28, SD = .67) and an on-site validation study ( n =180, 36% identifying as female; M a g e = 9.80, SD = .63) examining internal consistency, factor structure, and validity measures like reasoning and intelligence. Results showed diverse item difficulty and promising psychometrics that merit further investigation. Given the PfPT’s ease of administration in online and classroom settings, it is a valuable tool for future primary math research. • Development of a digital test for preformal proof competency in primary school children. • Demonstration of feasibility for large-scale use in educational and research settings. • Two studies (online and proctored) establishing reliability, dimensionality, and validity evidence. • First study to explore the nomological net of proof competency in this age group, including intelligence and computational thinking.