Student Inflation Basket Project

Use this three weeks project to teach inflation measurement through one concrete decision. Students build and interpret a price index while confronting weighting, substitution, quality, and data-consistency problems. Grade the decisions and the economic reasoning, not decoration or a lucky final number. The checkpoints make the process visible and keep the project from becoming a last-night slideshow.

The classroom prompt

Each team defines a 10-item student basket with fixed quantities, records base-period and current prices from the same outlets, calculates a class CPI, and compares its rate with an official index.

Put the question where every student can see it and do not supply vocabulary before students commit to an answer. Their first explanation becomes the evidence you use during the debrief.

Materials and setup

Teams need a fixed basket template, dated public prices from stable sources, a spreadsheet, and a source log. No purchases or personal spending data are required.

Open the inflation lesson if you want students to test the same idea on an interactive model after the paper task. A projected version is enough; students do not need accounts for this lesson.

Run the lesson

Answer key and teacher moves

• Index = current basket cost/base basket cost × 100; inflation = percentage change in the index.
• Quantities must stay fixed for a Laspeyres-style classroom CPI, or price and quantity changes become mixed.
• An item with a large expenditure weight can matter more than one with a larger percentage price increase.
• Substitution and quality change make a fixed-basket index an imperfect measure of cost of living.

Do not give credit for the correct direction alone. Ask students to name the changed determinant, identify the curve or quantity that changes, and connect the change to the final outcome. A complete explanation contains a cause, a model move, and a result.

What to collect

Use a 100-point rubric: 20 design, 25 source quality, 25 calculations, 20 economic evaluation, and 10 reproducibility.

Most likely misconception: Students average item inflation rates without expenditure weights or quietly change basket quantities between periods.

Support and extension: Provide a ten-item teacher dataset when collection is inaccessible. Extend by comparing Laspeyres and current-weight approaches.

A clean closing question

End with: What changed, what stayed fixed, and what evidence proves your conclusion? That sentence works as the final written check because it forces students to separate a cause from the movement it produces. Collect it, scan for the misconception above, and use the first three minutes of the next class to repair the pattern if needed.

This resource is ready to copy into a slide, handout, or LMS assignment. If you assign it for points, publish the success criteria before students begin: correct model, correct direction, and an explanation that links the two.