Marginal Revenue Product: Match Units Before Hiring

Units reveal whether a value belongs in the hiring rule.

Read Three Revenue-Product Calculations

For these examples, use the same stated production period throughout. Treat each quoted marginal-revenue amount as applying to all the output in the stated worker increment, and treat a quoted wage used for hiring as the entire added cost, with no other cost changes. These assumptions make the finite worker calculations exact; do not silently carry them into a different market or time period.

Define the Marginal Revenue Contribution

Marginal product measures added output per added input; marginal revenue measures added total revenue per added output. In a smooth model, their product gives the marginal revenue product of the input. For a whole-worker change, multiplying by a single MR is exact if it applies across that output increment; otherwise calculate the actual change in total revenue. Total product, total revenue and average revenue per worker do not become marginal hiring benefits just because they mention output or money.

Compare the Same Marginal Worker

If the sixth worker adds 12 units and each extra unit adds $7 to revenue, MRP is $84. At an $80 competitive wage, the worker should be hired. At $90, the worker should not. The comparison applies to the marginal worker, not to the average productivity of the whole workforce. Earlier workers may have much larger MRP, which is why a downward-sloping labor-demand schedule can coexist with hiring several workers at one wage.

Separate Physical Output from Added Revenue

A worker with high marginal product can have low MRP if the added output has little marginal revenue. Hiring depends on the revenue value of output, not physical output alone.

Match the Input Unit and Time Period

A dimensional audit checks the input unit and period as well as the currency. If output is measured per day and labor in worker-days, MRP is dollars per worker-day. Convert an hourly wage to the same hours before comparing it. Product price and MR both have dollars-per-output units, yet are different measures unless the model makes them equal. Likewise, a wage can have the same units as MRC without equaling the full added payroll cost.

Use the Unit Reference Table

The table abbreviates the time period; specify the same period on both sides of an actual calculation. Use the wage as MRC only when it is the full marginal input cost, as in the simple wage-taking case. With uniform-wage monopsony, hiring can also raise pay for existing workers. Extra benefit and extra cost must cover the same feasible change.

Value the Seventh Worker, Not the Average

Suppose the seventh worker raises output from 140 to 151. MP is 11. If price is $9 in competition, MRP is $99. If the wage is $94, hire. If it is $104, do not. Dividing total revenue by seven gives average revenue product per worker, which can look plausible but does not value the seventh worker.

Distinguish an Interval Average from Individual Increments

If a table changes labor by more than one worker, dividing the output change by the labor change gives an average increment across that interval. Output rising from 200 with 10 workers to 236 with 13 gives 36 ÷ 3 = 12 units per added worker across the interval. Without the missing rows, the separate eleventh, twelfth and thirteenth contributions cannot be recovered. This is not total output divided by total workers, and it does not establish a dollar value.

Reject the Wrong Units and Wrong Revenue Measure

A table reports MP of 8 units per worker, product MR of $6 per unit, total revenue of $480, and wage of $52 per worker. The hiring comparison is 8 units per worker × $6 per unit = $48 per worker versus a $52-per-worker wage. Total revenue cannot be compared with one worker’s wage, and MP cannot be compared with dollars.

Check the Product-Market Assumption

In an imperfectly competitive product market, price times added output can have the correct units yet miss the effect on revenue from other sales. Units are necessary, not sufficient. Verify whether the product-market model makes MR=P; otherwise use marginal revenue or the actual finite change in total revenue, including any price effects on existing sales.

Apply the Check to Other Inputs

The same discipline applies to capital or land. Replace “worker” with the input unit: marginal revenue product remains dollars per added input, and MRC remains the added dollar cost of obtaining it. The hiring rule is a general factor-use rule.

Write the Conditional Decision

End with a conditional decision: “The next worker adds $48 to revenue and $52 to total cost over the same period, so that hire reduces profit by $4.” This compares the stated feasible increment with not taking it; it does not determine the best workforce among every possible choice or settle a separate decision about operating at all.

Check the Hiring-Benefit Definition

OpenStax’s labor-market theory lesson connects hiring to the revenue value of a worker’s marginal output and distinguishes output-market assumptions. Use its definitions alongside the units in the question. No current wage rate, legal minimum or measured productivity effect is implied by the invented examples here.

For a continuous model, the chain rule links the marginal change in revenue with the marginal change in output. For a finite increment, the direct check is the difference in total revenue divided by the change in the input. A quoted wage is a valid cost comparison only if it captures the added cost for that same increment. Matching labels is a diagnostic step, not proof that every other model assumption holds.

Add Varying Revenue Increments over One Worker-Day

In an invented example, one additional worker-day produces five extra units. Their successive increments in total revenue are $12, $11, $10, $9 and $8. Those figures already include any effects on revenue from existing sales; they are not merely the five units’ sale prices. The extra worker-day costs $47, no other costs change, and this is a feasible choice. Does the worker-day add profit?

Try Three Unit-and-Hiring Questions

Connect Added Revenue to Added Hiring Cost

Compare marginal hiring cost under monopsony, distinguish the market wage from one firm’s hiring choice, and continue through the CLEP Microeconomics learning hub.