Lesson Rationale
A written commentary, attached to a lesson plan, that explains why each major decision was made. Where the procedure says what the teacher and learners do, the rationale says why this aim, this material, this sequence, this interaction pattern, this length — and what alternatives were considered and rejected. The rationale is foregrounded in DELTA-style assignments, in M-level teaching qualifications, and in any context where a plan is assessed not only on whether it would work but on whether the planner understands why.
What it covers
A full rationale typically addresses several layers. At the level of Lesson Aims, it explains what the cohort needs at this point in the course and why this lesson is positioned where it is. At the level of materials, it justifies the chosen text or task — its level, length, topic, fit with the aim, and any adaptations made. At the level of Staging, it accounts for the order: why a lead-in of this kind, why this stage before that one, why controlled practice precedes (or in some shapes follows) freer use. At the level of interaction, it explains who works with whom and why — pair, group, individual, mingle — given the learners' profile. Finally, it identifies the principles or research the planner is drawing on, so the assessor can see the link from theory to practice.
The rationale is not a description of what is hoped will happen. Vague gestures — "this stage will engage learners" — fail to count as rationale. Substantive rationale names a problem the stage is designed to solve, an alternative that was considered and rejected, or a research finding that motivates the choice.
Difference from reflection
Rationale is prospective; Reflective Practice is retrospective. The rationale explains decisions before the lesson is taught; reflection examines what actually happened against those decisions and what the gap reveals. Strong professional development cycles use both: a planned rationale establishes what the teacher believes and intends, the lesson tests that belief in practice, and post-lesson reflection compares the two and feeds back into the next plan. Many DELTA assignments require both an extended rationale and a reflective commentary, so that the assessor sees the teacher's reasoning at both points.
The rationale also serves the planner's future self. A teacher returning to a lesson months later can rebuild it from the procedure alone, but cannot recover why one option was chosen over another without commentary attached.
References
- Watkins, P. (2014). Learning to Teach English (2nd ed.). Delta Publishing.
- Harmer, J. (2015). The Practice of English Language Teaching (5th ed.). Pearson Education.