Choose an activity in one of three preference rounds, then identify the best available alternative you gave up. R1 choosing A gives up B; R2 choosing C gives up A; R3 choosing B gives up C because A is unavailable. Choosing B under R1 instead makes A the next-best alternative. The page explains the current choice without grading it as desirable.
Establish the resource constraint first
The St. Louis Fed's educational essay connects scarce resources, including time, with choice and defines opportunity cost through the next-best alternative forgone. Apply that definition to the single studio slot below. St. Louis Fed: Money and Missed Opportunities
The fictional class has exactly one ten-minute studio slot. Each option uses the entire slot:
| ID | Original activity | Required slot |
|---|---|---|
| A | Make a paper model | All ten minutes |
| B | Sketch a poster | All ten minutes |
| C | Work on a silent puzzle | All ten minutes |
Choose exactly one. Doing A and B together or shortening each into a five-minute version is outside this supplied model. The ten minutes are the constrained resource, not a monetary price or a measured utility.
For a new scenario, specify which activities are feasible before asking students to rank them.
Separate availability from preference
Availability asks whether the option can be done in this slot. Preference ranks the available alternatives; it does not make an unavailable activity feasible.
The three original round cards are independent:
| Round | Feasible set | Supplied ranking | Worked choice |
|---|---|---|---|
| R1 | A, B, C | A preferred to B, then C | A |
| R2 | A, B, C | C preferred to A, then B | C |
| R3 | B, C; A unavailable | B preferred to C | B |
The supplied rankings belong to this hypothetical class. Ask students to reason from them for this exercise, then discuss how their own preferences might change the answer.
Changing R1 to R2 changes the supplied preference order, not the amount of time or the activities' durations. R3 changes feasibility as well as the displayed ranking. Do not carry R1's answer forward automatically.
Identify the next-best remaining feasible option
For each worked choice, remove the chosen activity from the feasible set and find the highest-ranked remaining option.
| Original key | Chosen activity | Next-best feasible alternative forgone |
|---|---|---|
| R1 | A paper model | B poster sketch |
| R2 | C silent puzzle | A paper model |
| R3 | B poster sketch | C silent puzzle |
For R1, B ranks above C, so B is the next-best alternative. B and C together were never a feasible use of the one slot. Adding their supposed benefits would answer a different question.
The exercise identifies the forgone activity and discusses its benefit qualitatively. It does not measure that benefit in dollars or numeric utility. The opportunity-cost concept concerns the value of that next-best alternative; naming B is the activity-level identification, not a price estimate.
For R2, the worked choice C gives up A as next best. A paper model is not a fixed universal opportunity cost; it depends on the chosen activity and ranking.
For R3, A is unavailable and cannot be the next-best feasible alternative. Among B and C, choosing B gives up C.
Keep the chosen benefit distinct from what was forgone
The page asks for your choice, the next-best alternative's ID, and a reason. Discuss the benefit of the chosen activity separately; there is no dedicated chosen-benefit field.
A worked R1 explanation can say The supplied order ranks A first; choosing it uses the only slot. B is the highest-ranked remaining feasible use, while C ranks below B. That explains both the choice and the forgone alternative without adding B and C together.
Making the paper model is a benefit of choosing A; the poster sketch is the alternative forgone under R1's ranking. Do not call the ten-minute chosen activity itself the next-best option lost.
Teacher review can accept paraphrases that preserve the constraint and ranking. It should not exact-string grade the explanation or assign points for wanting the teacher's preferred activity.
Check a conditional answer
Choose one feasible activity, enter its next-best alternative ID and a reason, then check the fixed relationship. The explanation remains for teacher review. Changing a choice clears its old next-best answer and key; changing the round clears the prior choice too. Reset restores R1 with blank responses.
Use the reveal only after selecting an available activity. The key follows the chosen activity, not a universal paper-model answer. Actual learner rankings can differ and belong in a separate reasoning record, where ties or missing information remain questions to discuss.
Copy a prompt for this example
Build one self-contained HTML opportunity-cost activity with embedded CSS and JavaScript. Use a classroom choice-board layout with a visible time constraint, round buttons, three activity buttons, a labeled alternative-ID field, and a written reason field.
The class has exactly one ten-minute studio slot. A is making a paper model, B is sketching a poster, and C is working on a silent puzzle. Each uses the entire slot, so combinations are unavailable.
Provide three rounds. R1 makes A, B, and C available and ranks A above B above C. R2 makes all three available and ranks C above A above B. R3 makes only B and C available and ranks B above C; disable A.
Let the learner choose any feasible activity. Compute the answer by removing that choice and taking the highest-ranked remaining feasible option. Under R1, choosing A gives up B, while choosing B gives up A. Under R2, choosing C gives up A. Under R3, choosing B gives up C.
Require a choice, an alternative ID, and a nonblank reason before Check. Check the fixed ID relationship while leaving reasoning for teacher discussion. Do not grade whether the learner's chosen activity is desirable.
Include a key reveal that requires a choice. Changing the choice clears the old answer, reason, and key. Changing rounds clears the choice too. Reset restores blank R1. Keep the rankings explicitly hypothetical and avoid invented monetary values. Return only the complete HTML file.
For the next scarcity discussion, NOS can display this prepared HTML choice activity. Compare R1’s worked choice with the conditional choice B, then ask students to name the forgone benefit without assigning invented dollar values.