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CMA Final · Strategic Cost Management

Throughput Accounting for CMA Final Strategic Cost Management

Throughput Accounting judges products and decisions by throughput, which is sales minus totally variable cost (usually direct material), earned per unit of the bottleneck resource. To solve a question, find the bottleneck, rank products by throughput per bottleneck hour, fill capacity in that order, then recommend.

What this chapter covers

Throughput Accounting (TA) is a decision tool built on the Theory of Constraints. It starts from one idea: a business can earn only as much as its scarcest resource allows. So you stop spreading overheads over products and instead ask how to earn the most from the constraint.

The chapter moves in a clear line. You learn the definitions (throughput, investment, operating expense), then the Theory of Constraints and how to identify a bottleneck. Next come the measures and ratios, then product mix decisions when capacity is limited. It ends by comparing TA with absorption and marginal costing.

In Paper 16 this chapter links to marginal costing and limiting factor analysis, activity-based costing, pricing and other decision-making topics. It also supports the case-based thinking that written answers demand: you work out the numbers, then give a clear recommendation.

The chapter is short and calculation-driven, so it is a good place to score if you practise the standard workings. It can appear as a 2-mark MCQ on definitions or ratios, or as a written question on product mix with a recommendation. Examiners reward the right ranking basis and a clear conclusion. Students who confuse throughput with contribution, or rank on the wrong measure, lose marks easily, so careful practice pays off.

Throughput Accounting: topics in the order to study them

  1. 1Introduction to Throughput AccountingIt gives the definitions of throughput, investment and operating expense that every later topic uses.
  2. 2Theory of Constraints and BottlenecksYou need to identify the constraint before any ratio or ranking makes sense.
  3. 3Throughput Measures and RatiosOnce the bottleneck is known, you can calculate throughput per bottleneck unit and the TA ratio.
  4. 4Product Mix Decisions Under ConstraintsThis applies the measures to choose the best mix, which is the main numerical question type.
  5. 5Throughput Accounting vs Traditional CostingThe comparison is easier once you have worked the numbers, and it supports theory and MCQ answers.

How to prepare Throughput Accounting

Treat this as a method chapter. Learn the steps once, then repeat them on varied problems until they become automatic.

  1. Write the definitions in your own words: throughput = sales − totally variable cost (usually direct material), and operating expense = all other costs, treated as fixed in the short run.
  2. Learn the five focusing steps of the Theory of Constraints in order: identify, exploit, subordinate, elevate, repeat.
  3. Practise finding the bottleneck: compare the hours each resource needs for the planned output with the hours available, and pick the resource with the greatest shortfall.
  4. Memorise the core calculations: throughput per bottleneck hour, cost per bottleneck hour = total factory cost ÷ bottleneck hours, and TA ratio = throughput per bottleneck hour ÷ cost per bottleneck hour.
  5. Solve product mix problems in a fixed pattern: calculate throughput per unit, divide by bottleneck time, rank, allocate hours up to demand limits, and compute total throughput less operating expense.
  6. Always finish with a recommendation in a sentence or two, and note any assumptions such as fixed labour cost or no extra capacity.
  7. Prepare a short comparison list of TA against absorption and marginal costing, covering inventory valuation, treatment of labour and overheads, and focus.

Common mistakes in Throughput Accounting

  • Ranking products by throughput per unit instead of per bottleneck hour

    Fix: Divide throughput per unit by the bottleneck minutes or hours each unit needs, then rank on that figure.

  • Treating direct labour as a variable cost in throughput

    Fix: Follow the question. Under standard TA, only totally variable costs such as materials are deducted, and labour goes into operating expense unless the question says it varies.

  • Picking the wrong bottleneck

    Fix: Compute total hours required for the demanded output and compare with hours available for each resource. The largest shortfall is the bottleneck.

  • Ignoring demand limits when filling capacity

    Fix: Allocate to the top product only up to its maximum demand, then move to the next, and use the remaining hours for the last product.

  • Ending with numbers and no recommendation

    Fix: State which products to make, in what quantity, the resulting profit, and one line on what to do about the constraint.

  • Mixing up cost per bottleneck hour with absorption rates

    Fix: Use total factory cost, including labour and overheads, divided by bottleneck hours, and use it only for the TA ratio.

Last-day revision: Throughput Accounting

  • Throughput = sales revenue − totally variable costs, usually direct material.
  • Operating expense = all costs other than totally variable costs, such as labour and overheads, treated as fixed in the short run.
  • Investment in TOC covers inventory, equipment and other assets tied up in the system.
  • The bottleneck is the resource that limits system output; time lost there is lost for the whole system.
  • Five focusing steps: identify, exploit, subordinate, elevate, repeat.
  • Rank products by throughput per bottleneck hour, not by throughput per unit or contribution per unit.
  • Cost per bottleneck hour = total factory cost ÷ available bottleneck hours.
  • TA ratio = throughput per bottleneck hour ÷ cost per bottleneck hour; above 1 means the product covers its cost.
  • Profit = total throughput − operating expense.
  • Under TA, inventory is valued at material cost only, so there is no incentive to overproduce.
  • Improving a non-bottleneck adds no throughput; extra capacity at the bottleneck does.
  • After you elevate a constraint, check where the bottleneck moves.

Throughput Accounting practice questions

Throughput Accounting in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Throughput Accounting: frequently asked questions

What is the difference between throughput and contribution?

Throughput deducts only totally variable costs, usually direct material. Contribution deducts all variable costs, so labour and variable overheads are also removed if they vary. Always follow the definition given in the question.

How do I find the bottleneck in a numerical question?

Calculate the hours each resource needs to meet the demanded output and compare with hours available. The resource with the biggest shortfall, or the highest utilisation above 100%, is the bottleneck.

What does a TA ratio above 1 mean?

It means throughput earned per bottleneck hour is more than the cost per bottleneck hour, so the product adds to profit. A ratio below 1 means it does not cover the factory cost for the time it uses.

Is Throughput Accounting only for the written section?

No. Definitions, ratios and the comparison with other costing methods suit 2-mark MCQs. Product mix and ratio calculations suit written questions that need a recommendation.