Pedagogical approaches to teaching recursion in secondary computer science education: a comparative analysis of teaching materials

Background and Context Recursion represents a powerful programming technique, important for computer science education, yet students consistently struggle with recursive concepts. Despite more than four decades of research, little attention has been paid to how different national education systems structure recursion instruction through actual teaching materials.Objective This study examines how four countries (Croatia, the United Kingdom, Singapore and Indonesia) approach recursion instruction in secondary education (ages 13–18) through analysis of teaching materials, identifying common elements and significant variations.Method We conducted systematic qualitative document analysis of teaching materials at equivalent granularity: curriculum-aligned textbooks, official curriculum guides and government-published instructional resources. This ensures valid comparison by examining teaching materials rather than comparing curriculum specifications to instructional resources. Documents were coded according to five dimensions: placement, pedagogy, examples, difficulty strategies and assessment methods.Findings All four countries introduce recursion at upper secondary level (ages 16–18) using factorial and Fibonacci as primary examples. Significant variations exist in pedagogical frameworks and efficiency instruction. Croatia provides early conceptual introduction at age 13–14 and explicit efficiency instruction including memoisation. The United Kingdom emphasises recursion–iteration comparison through trace tables. Singapore mandates explicit stack understanding. Indonesia employs formal mathematical notation. The near-universal omission of explicit efficiency instruction represents a significant gap.Implications Effective recursion pedagogy benefits from multi-modal instruction combining mathematical formalism, visual representation, mechanistic understanding and performance considerations. These elements are rarely found together. Examining teaching materials rather than curriculum specifications alone is essential for understanding pedagogical approaches.