Three-Phase Lesson¶

Strategy · All strategies
Evidence · 4 claims (3 for, 1 mixed) · 11 studies (5 causal, 5 quant-synthesis, 1 theoretical), q2–q4 · 5 of 11 report an effect size

Description¶

The Three-Phase Lesson organizes a single lesson into three sequenced phases: Before (activating prior knowledge, framing the task, establishing expectations), During (students actively work on a problem, task, or investigation while the teacher circulates, questions, and supports), and After (consolidation — students share strategies, the teacher highlights key ideas, and connections are made explicit). The structure is most closely associated with mathematics instruction (e.g., Ontario's "Getting Started / Working On It / Reflect and Connect" framework) but generalizes to any problem- or inquiry-based lesson. It is a lesson-level architecture rather than a single technique: each phase draws on distinct elements, and the value comes from the deliberate handoffs between them.

Design Implications¶

The structure operationalizes two well-supported ideas: activating prior knowledge before new content improves learning Activation improves learning. [+M], and consolidation after active work is where partial understanding gets organized into usable form. The During phase enacts Active Learning, which improves exam performance relative to lecture alone Active learning improves exam performance. [+S]. The After phase is frequently truncated in practice, yet it carries much of the conceptual payoff — without it, learners leave with strategies but not the connections among them.

Context¶

Requirements¶

• A rich, solvable task for the During phase that permits multiple solution approaches
• A Before phase that activates relevant prior knowledge without giving away the solution path (Activation)
• Time protected for consolidation — typically as much as a third of the lesson
• A teacher role during the During phase of monitoring and questioning, not rescuing (Practice, Check-In)

Constraints¶

• Compressing the After phase into "here's the answer" forfeits the consolidation benefit and can leave misconceptions intact [-M]
• A Before phase that over-scaffolds (teaching the method the task was meant to elicit) turns the During phase into procedure-following rather than problem solving [~M]
• Low-floor tasks are required; a task most students cannot enter makes the During phase unproductive for much of the class [-M]
• The structure adds time overhead relative to direct presentation; for novices with minimal prior knowledge, a full exploration cycle may overload working memory Cognitive overload degrades learning. [~S]

Implementation Variability¶

• Mathematics lesson study versions (e.g., Toronto District School Board's three-part lesson) emphasize bansho/consolidation boards where student work is sequenced publicly in the After phase
• Launch–Explore–Summarize (Connected Mathematics Project) applies the same arc to middle-school investigations
• 5E Learning Cycle extends the arc to five phases (Engage, Explore, Explain, Elaborate, Evaluate) for science
• In literacy blocks, the arc appears as mini-lesson → independent work → share

Target Learners¶

• K–12 learners in problem-based subjects, especially mathematics Active learning improves exam performance. [+S]
• Mixed-ability classes — the During phase permits differentiated support while students work on a common task
• Learners with weak prior knowledge need a deliberately brief, targeted Before phase; too little activation leaves them searching blindly Activation improves learning. [~M]

Target Learning Goals¶

• Conceptual understanding through comparing student-generated strategies Comparing contrasting cases improves learning. [+S]
• Procedural fluency built on self-generated methods rather than transmitted procedures
• Mathematical discourse and explanation (the After phase's share-and-connect routine)

Instructions¶

1. Before (5–10 min): Activate relevant prior knowledge with a brief related task or discussion (Activation, Advance Organizers); present the problem and clarify expectations without demonstrating the solution method.
2. During (15–25 min): Students work — individually, in pairs, or in groups (Collaborative Learning) — while the teacher circulates, asks assessing and advancing questions, and selects students whose work will anchor the consolidation (Check-In).
3. After (10–15 min): Sequence selected student solutions from concrete to abstract, have students explain and compare approaches (Comparing Cases), and name the key mathematical idea (Clear Structure); assign a consolidation or extension task.

Related Strategies¶

• Worked Examples — an alternative Before-phase move when exploration would overwhelm novices; can be interleaved with the three-phase arc across a unit
• Think-Pair-Share — a common During-phase participation structure
• Gallery Walk — an After-phase format for sharing and critiquing student work
• Teachers as designers and guardians of the task structure across all three AIRIS phases

Examples¶

• Connected Mathematics Project (CMP) — [https://www.mheducation.com/prek-12/program/microsites/MKTSP-OIP01M0.html] — middle-school units structured as Launch, Explore, Summarize.
• Ontario Ministry of Education three-part lesson — "Getting Started / Working On It / Reflect and Connect," widely used in Ontario elementary mathematics and in lesson study cycles.
• Illustrative Mathematics (IM K–12) — [https://illustrativemathematics.org] — lesson plans with a warm-up (Before), activity (During), and lesson synthesis (After), including explicit "cool-down" checks.

Key Sources¶

• Ontario Ministry of Education. (2011). Paying attention to mathematics education, K–12. Queen's Printer for Ontario. https://www.edu.gov.on.ca/eng/teachers/studentsuccess/PayingAttentiontoMathematics.pdf
• Freeman, S., Eddy, S. L., McDonough, M., Smith, M. K., Okoroafor, N., Jordt, H., & Wenderoth, M. P. (2014). Active learning increases student performance in science, engineering, and mathematics. Proceedings of the National Academy of Sciences, 111(23), 8410–8415. doi:10.1073/pnas.1319030111
• Schwartz, D. L., & Bransford, J. D. (1998). A time for telling. Cognition and Instruction, 16(4), 475–5223. doi:10.1207/s1532690xci1604_4
• Stein, M. K., Engle, R. A., Smith, M. S., & Hughes, E. K. (2008). Orchestrating productive mathematical discussions: Five practices for helping teachers move beyond show and tell. Mathematical Thinking and Learning, 10(4), 313–340. doi:10.1080/10986060802229675