Teacher's Guide

Learning objectives

• Explain Selection effect and Identification in the context of this lesson.
• Use the worked example to answer the three practice questions with supporting reasoning.
• Complete the activity, evaluate its result, and identify one limitation or possible improvement.

Prerequisites: The preceding grade sequence or equivalent introductory knowledge; begin with a short vocabulary review.

Suggested time: Three to five 45-minute sessions, including activity development and review. Language units need brief repeated spoken practice between sessions.

Teaching sequence

1. Introduce: Present the title as a question or problem. Ask learners what they notice and record two initial ideas without treating them as established facts.
2. Explain: Read the concept section and teach the two vocabulary items. Ask learners to paraphrase the distinction between them using a concrete example.
3. Model: Work through the example. Identify given information, assumptions, and the reason for the result or interpretation. Use a teacher's spoken model for language pronunciation.
4. Apply: Complete the activity individually or in pairs. Require a draft, a check against the task, and a brief revision. Discuss why different justified responses may be acceptable.
5. Retrieve and evaluate: Answer practice and vocabulary questions independently; use the answer key for feedback. Finish with the reflection and an activity rubric.

Assessment and differentiation

The companion CSV contains five retrieval entries: two vocabulary questions and three practice questions. Award one point per accurate answer, accepting equivalent wording that preserves the meaning. Language answers may be oral or written according to the goal. Revisit missed concepts rather than using the score as the only measure of learning.

Assess the activity separately with four criteria, each scored 0-2: correct use of lesson concepts; clear evidence or reasoning; completion of the task requirements; and a useful revision or acknowledged limitation. A 0 indicates missing or unsupported work, 1 indicates partial achievement, and 2 indicates clear achievement. Accept multiple designs, interpretations, and decisions when their reasons meet the criteria.

Support learners with a word bank, annotated example, smaller first step, or partner rehearsal. Extend by changing one assumption or constraint and asking how the result would change. Use invented personal details in financial and social tasks. Optional school character discussion can connect honesty, respect, cooperation, and stewardship to the activity; assess the subject knowledge and reasoning separately.

Student Worksheet

Concept and helping material

An economic study needs a clear question, suitable measures, and a design that addresses alternative explanations. Selection effects arise when participants differ systematically before an intervention. A before-after comparison can reflect unrelated changes. Identification concerns whether the evidence can distinguish the proposed effect from alternatives.

Vocabulary

• Selection effect: A difference associated with how people or cases enter a studied group.
• Identification: The ability of a design to distinguish the effect of interest from alternative explanations.

Worked example

A fictional school observes higher scores after tutoring, but participants had different prior motivation and other support. The raw change does not isolate tutoring's effect.

Investigation or design task

Critique a teacher-created intervention dataset. Identify selection and timing problems, propose an improved comparison, and write a conclusion within the evidence's limits.

Record your work: State the goal; show your drawing, dialogue, calculation, data, or argument; explain one choice; and describe one check or revision. Identify a limitation rather than claiming your work proves more than it does.

Practice

1. Does a before-after score rise alone isolate a treatment effect?
2. Why compare initial conditions?
3. What should a cautious conclusion state?

Vocabulary retrieval

1. Define Selection effect.
2. Define Identification.

Reflection

Choose one answer or activity decision. Explain the evidence, calculation, language pattern, or reasoning that supports it. Describe one change of context or assumption that could change your conclusion.

Answer Key

1. No.
2. Groups may differ before the intervention begins.
3. The observed association and what the design cannot establish causally.

Vocabulary answers are the definitions above and appear in the CSV. Activity and reflection responses vary; use the teacher rubric and require specific reasoning tied to the task. A different supported interpretation is acceptable where the question allows it.

Source Reference

Original teaching material. No directly matching, age-appropriate lesson reference was identified in the supplied G7-12 PDF collection. No external research is claimed.

Companion question CSV | Grade guide