Opportunity cost: the next-best alternative

Paper packet. Every task here also exists on screen, where it is checked automatically; answers written on paper are not assessed by Nydus. When you are back at a device, enter your answers there.

1. What you will learn

You will identify the best feasible alternative forgone and its supplied value. Calculate the chosen plan's net advantage separately, explain why incompatible alternatives are not added, and avoid counting the same expense twice. Recognize that a feasible alternative can be a bundle and that money can measure an opportunity cost under suitable assumptions.

2. Starting point

Use the stated alternatives, quantities and units. Separate a model's assumptions from the conclusion derived from them.

3. Terms to use precisely

4. Name the alternative and its value

Opportunity cost is the value of the best feasible alternative forgone when a choice is made. It connects two questions: what would the resource otherwise have been used for, and what value does that alternative have under the stated comparison? A workshop that builds a shelf instead of repairing a table gives up the repair. If the exercise supplies a comparable value for the repair, that value measures the opportunity cost of using the workshop time for the shelf.

Sometimes naming the alternative is the most informative answer. The cost of attending a rehearsal may be missing a friend's visit. There is no need to invent a money value when the case supplies none. In a numerical exercise, the values must be given or derived from a stated rule. We do not assume that personal relationships, leisure, or every social benefit can be measured accurately in dollars merely because arithmetic is convenient.

Our basic tables give complete mutually exclusive plans and comparable net values in teaching units. Net means that the directly attributable resource expenses specified for that plan have already been deducted. This assumption prevents us from subtracting those expenses again. The plans use the same constrained resource over the same period. Their values can therefore be compared within the exercise, although that does not establish a universal measure of their importance.

The calculation is not the value of the chosen plan minus every other plan. Identify the best feasible unchosen plan first. Its value is the opportunity cost. If you then subtract that value from the chosen plan's value, the result is the chosen plan's net advantage relative to the best alternative. Opportunity cost and net advantage are related but different quantities, so keep their labels separate.

Term	What it means
Opportunity cost	The value of the best feasible alternative forgone.
Net value	The supplied value after the expenses specified in the model have already been deducted.
Net advantage	Chosen value minus the value of the best feasible alternative.
Double counting	Counting the same resource sacrifice more than once.
Counterfactual comparison	Comparing the chosen plan with what would happen under a feasible alternative.

Another way: Use the best feasible alternative, not a sum

Suppose a machine can perform one of three jobs this morning. Their supplied net values are twenty, sixteen, and eleven units. If the twenty-unit job is chosen and the other two are feasible, the opportunity cost is sixteen. The machine could have performed the sixteen-unit job instead. Adding sixteen and eleven would count a combination the machine cannot complete within the morning. The forgone value must come from a feasible replacement plan.

The lower-valued job may still be useful. Its value does not become zero because it is not the best alternative in this comparison. If the sixteen-unit job becomes unavailable, the eleven-unit job may become the new opportunity cost. This change illustrates why costs depend on available alternatives. The chosen twenty-unit job can remain unchanged while its opportunity cost falls because the menu changes.

A feasible replacement can be a bundle. If two small jobs jointly fit the morning and produce a combined net value of eighteen, that bundle may be better than the sixteen-unit job. The rule does not forbid adding values within a genuinely feasible plan under an additive-value assumption. It forbids adding mutually incompatible plans as though they could all replace the chosen one. Always check what the resource constraint permits.

Likewise, the best alternative need not be an active production plan. Waiting, resting, storing a resource, or declining a project can be feasible choices with relevant value. A numerical question must state how those options enter the comparison. Do not assume that every choice necessarily sacrifices a positive measured amount when the exercise's feasible alternatives and valuation could make the relevant cost zero.

Another way: Money is a resource and a possible unit of account

A money payment and an opportunity cost answer different questions, but they are not unrelated. A twelve-dollar purchase uses money that could have bought something else. Under a stated budget and known prices, we can describe that forgone purchasing power in units of the alternative good. In suitable comparisons, a dollar amount can represent an opportunity cost. It would be too strong to say that money can never measure the cost of a choice.

A price alone may omit other resources used by the decision. Attending an event can require travel time as well as a ticket payment. The relevant alternative uses of time and money should be considered together as feasible plans. If skipping the event would allow both a different purchase and a different use of the evening, the alternative plan may contain both. Avoid treating the whole evening and the whole budget as if they could each independently support incompatible activities.

Double counting is a common danger. If a supplied net value already subtracts the ticket and travel expenses, do not subtract those expenses again from that same value. Similarly, do not add the cash price and the value of the exact goods that same cash could buy as two independent sacrifices. They are different descriptions of the same use of the budget unless the model clearly identifies additional resources.

State the unit of the answer. Six dollars, three notebooks, and two hours are different quantities. An opportunity-cost statement should make clear what is being forgone. The next lessons explore money and time constraints separately, while retaining this discipline: specify the alternative, measure it using the supplied information, and avoid counting one sacrifice twice.

Another way: A positive opportunity cost does not prove a mistake

Choosing a plan with a valuable alternative can still be sensible under the stated objective. If the selected job produces twenty units and the best feasible alternative produces sixteen, the opportunity cost is sixteen and the net advantage is four. The existence of the sixteen-unit sacrifice does not show that the selected job is inferior. It shows that the comparison should include what could have happened instead.

Conversely, a positive payoff from the chosen plan does not establish that it is best. Suppose it produces twenty units while another feasible plan produces twenty-three. The opportunity cost is twenty-three, and the net advantage of the selected plan relative to that alternative is negative three. The selected plan has a positive value, but it performs worse under the stated criterion. Comparing only with doing nothing would hide the better available option.

This conclusion is conditional on the supplied values and objective. A real decision maker may care about risk, distribution, obligations, or other features missing from a simplified table. Identifying a negative difference in the toy model does not authorize pretending those omitted considerations never matter. It does identify what follows if the task's values are complete and its criterion governs the choice.

When you report a negative net advantage, keep the opportunity cost itself distinct. In the twenty-versus-twenty-three example, the opportunity cost is twenty-three; negative three is the comparison result. These exercises use nonnegative alternative values, so a negative opportunity-cost answer usually signals that you subtracted too soon or answered the second question in the first field.

Another way: Build and check a complete comparison

Begin by identifying the chosen plan and the scarce resource it uses. Next remove plans that the case explicitly marks unavailable. Among the remaining unchosen plans, find the highest supplied value. Record both its label and its value. This keeps the economic interpretation attached to the number rather than reducing the lesson to selecting a maximum with no explanation of what the maximum means.

Only then calculate the net advantage: chosen value minus the value of the best feasible alternative. Check the sign against the ranking. If the chosen plan has the largest value, the difference should be nonnegative. If a better feasible plan exists, it should be negative. This check catches reversed subtraction and helps distinguish an arithmetic slip from a misunderstanding of opportunity cost.

Check the resource boundary as well. A comparison between one morning of machine use and a whole week's output is invalid unless the figures have been converted to the same period. A highly valued but impossible plan is not a feasible alternative. A bundle using twice the available budget cannot become the opportunity cost merely because its listed benefit is high. The best alternative must survive both the value comparison and the feasibility check.

Finally state what could change the result. A new feasible option, a revised valuation, a different constraint, or a change in the chosen plan can change opportunity cost. Naming one of these conditions makes the comparison reviewable. You can explain why an answer is correct under the present assumptions without suggesting that the same number must remain correct in every future situation.

5. Choosing a repair project

A fictional repair club has one Saturday machine slot. Three complete jobs are feasible: plan A produces a supplied net value of twenty-eight teaching units, B twenty-two, and C seventeen. The values already deduct each job's stated material expenses and refer to the same machine time. If the club chooses A, the best feasible forgone plan is B. The opportunity cost is twenty-two units, while A's net advantage over B is six.

A volunteer points out that C also has value. That is correct, but adding C's seventeen to B's twenty-two would imagine two complete jobs in a slot that fits only one. C is not worthless; it simply is not separately added to the opportunity cost of A under this menu. If B's required part fails to arrive, C becomes the best feasible alternative and the opportunity cost falls to seventeen.

The club next considers a bundle D consisting of two shorter repairs that jointly fit the slot. Its supplied net value is twenty-five units. If D is feasible and A remains chosen, D becomes the best alternative and the opportunity cost rises to twenty-five. The net advantage of A is now three. The rule treats D as one feasible plan, even though it includes two tasks.

These results help the club understand the assumptions behind its comparison. They do not show that every benefit can be measured exactly or that the highest teaching-unit figure is a complete ethical verdict. They show how to avoid missing alternatives, infeasible sums, and double-counted expenses when comparing plans within the stated model.

6. Check the tempting inference

Do not confuse opportunity cost with net advantage. Do not add incompatible alternative plans or deduct expenses twice. A money amount can measure an opportunity cost under suitable assumptions; a price alone need not capture every relevant resource. A positive cost does not establish that a choice is mistaken.

7. Cost and advantage are different

8. A positive payoff can still be inferior

9. A bundle changes the comparison

10. Finish an unavailable-option comparison

11. Guided practice

One slot fits one plan. Net values are A=24, B=18, C=13; all feasible and A chosen. Give best forgone label, opportunity cost, and net advantage.

12. Guided practice

One slot fits A=15, B=12 or C=9 net units; A is chosen. Complete the comparison.

13. Guided practice

All plans fit the same slot: A=19, B=27, C=16 net units. A is chosen. Give best forgone label, cost and signed net advantage.

	Your result
Best forgone label
Opportunity cost in units
Net advantage in units