## Key Ideas > [!abstract] Core Concepts > > - **Manufacturing efficiency doesn't transfer to education**: Teaching content only when needed for problems causes cognitive overload > - **Prerequisites need extensive practice**: Students require fluency in foundational skills before complex applications > - **Bundling creates confusion**: Attempting to teach multiple prerequisite skills during worked examples overwhelms working memory ## Definition **Just-In-Time Teaching**: Educational approach attempting to teach content only when required for problem-solving, which is ineffective due to cognitive load limitations. ## Connected To [[Cognitive Load Theory]] | [[Fluency]] | [[Prior Knowledge]] | [[Worked Examples]] | [[Part-whole approach]] | [[Explicit Teaching]] --- ## Business vs. Education Context Just-In-Time manufacturing matches production to demand, reducing waste by supplying goods only when ordered. In education, this approach translates to teaching algebraic equations only when needed for measurement problems, or introducing fraction operations mid-problem during worked examples. This approach fails in education because students require extensive practice to become fluent in foundational skills (Rosenshine, 2012). Deficient prerequisite knowledge creates cognitive overload (Sweller et al., 2019). Unlike manufacturing materials that arrive fully functional, mathematical skills require development time before use. ## The Cognitive Load Problem Working memory has finite capacity. When students lack automated prerequisite skills, their mental capacity is consumed by basic operations rather than new learning (Cowan, 2001). Students struggle with fraction addition when they cannot quickly find common denominators. Algebraic problem-solving fails due to computational weaknesses. Multi-step solutions break down at basic arithmetic. ## Craig Barton's Fraction Addition Example > [!cite] Teaching Fraction Addition Problems > When teaching Year 7s fraction addition, I was aware of prerequisites - finding common denominators, transforming numerators, simplifying - but didn't worry much because I could cover them during the worked example. > > Midway through explanations I'd stop: "Beth, what's a good denominator choice? Sam, what's the numerator now?" When difficulties arose, I'd find board space to resolve problems then return to the main example. > > By bundling everything together, students couldn't process it all, and I had to play detective to understand which prerequisite skills were missing. The problem is clear: attempting to teach multiple prerequisite skills simultaneously during complex demonstrations exceeds working memory capacity (Pollock et al., 2002). Students cannot simultaneously learn new procedures whilst applying them to solve problems. ## Better Approach: Sequential Skill Building Teaching prerequisite skills before attempting complex procedures requires three steps. Basic skills must be automated through sufficient practice before introducing new applications. Practice should be targeted to address weak areas, with assessment verifying mastery before proceeding. A part-whole approach breaks down complex tasks into component skills, allowing students to master each before combining them (Catrambone, 1998). This systematic progression starts by identifying all required sub-skills, sequencing them from simple to complex, and building fluency before integration. ## Implementation Guidelines Assessment must come first. Use diagnostic questions to identify gaps before teaching complex procedures. The 80% rule provides a decision threshold: ensure most students demonstrate prerequisite competence before advancing (Wilson et al., 2019). Explicit pre-teaching requires dedicating time to building foundation skills rather than cramming them into complex examples. Fluency focus means providing sufficient practice for automatic recall of basic procedures so students no longer need conscious attention on fundamentals. Strategic timing involves planning ahead by building prerequisites into curriculum sequence rather than addressing them reactively. Maintenance practice should continue reinforcing basic skills throughout complex learning sequences, preventing previously learned skills from fading. ## References Catrambone, R. (1998). The subgoal learning model: Creating better examples so that students can solve novel problems. *Journal of Experimental Psychology: General*, 127(4), 355-376. https://doi.org/10.1037/0096-3445.127.4.355 Cowan, N. (2001). The magical number 4 in short-term memory: A reconsideration of mental storage capacity. *Behavioral and Brain Sciences*, 24(1), 87-114. https://doi.org/10.1017/S0140525X01003922 Pollock, E., Chandler, P., & Sweller, J. (2002). Assimilating complex information. *Learning and Instruction*, 12(1), 61-86. https://doi.org/10.1016/S0959-4752(01)00016-0 Rosenshine, B. (2012). Principles of instruction: Research-based strategies that all teachers should know. *American Educator*, 36(1), 12-19, 39. Sweller, J., van Merriënboer, J. J. G., & Paas, F. (2019). Cognitive architecture and instructional design: 20 years later. *Educational Psychology Review*, 31(2), 261-292. https://doi.org/10.1007/s10648-019-09465-5 Wilson, K., Raven, M., & Loaiza, V. (2019). *Active student responding: The big 5 instructional practices that promote student success*. SafeSchools.