# Structuring any business problem: the profitability case Source: https://sarang.pro/profitability-case-profit-tree/ Author: Sarang | Published: 25 October 2026 "Profit is down" is one of the most common problems a business brings to a consultant, and one of the most common cases in consulting interviews. It sounds like one problem. In practice it could be a dozen different ones: a competitor cutting prices, a supplier raising them, a quiet shift towards cheaper products, or a new office lease nobody questioned. The profitability tree is the standard way to work out which. It splits profit into parts that can't overlap, so you can measure each part, find the branch where the money went, and only then start thinking about fixes. This guide explains the tree, the two splits that matter most, and the order consultants work through a profit decline. ## The profit tree Everything starts with one line: profit equals revenue minus costs. Each side then splits again. - Revenue equals price multiplied by volume (the number of units, orders or customers sold). - Costs equal fixed costs plus variable costs. That gives four branches: price, volume, fixed costs and variable costs. Because the split comes from arithmetic, it is complete by construction. Every pound of profit change has to sit in one of the four, which is why this tree makes a good first cut for almost any business. In interviews and in most client work the profit in question is operating profit (earnings before interest and tax). [Management Consulted's guide to the framework](https://managementconsulted.com/profitability-framework/) recommends exactly this focus, setting interest and tax aside so the analysis stays on things management runs day to day. Below the four branches, you tailor. Price might split into list price, discounts and product mix. Volume might split into number of customers multiplied by purchases per customer, or market size multiplied by market share. Variable cost might split into materials, packaging and delivery. The top of the tree stays the same for every business. The lower levels should sound like the business you are looking at. ## Price versus volume Revenue can fall because you sell fewer things or because you get less for each one. The fixes are very different, so separate them early. Price problems include discounting, promotions that never end, a rival undercutting you, and mix shift. Mix shift is easy to miss: the price of each product hasn't changed, but customers are buying more of the cheaper ones, so average revenue per unit falls. Volume problems include a shrinking market, lost share, fewer new customers, lower repeat buying or a broken sales channel. The useful question here is whether the cause is outside (the whole market fell) or inside (you lost ground to others). Price also tends to have the larger effect on profit. In [The power of pricing](https://www.mckinsey.com/capabilities/growth-marketing-and-sales/our-insights/the-power-of-pricing), a 2003 McKinsey Quarterly article, the authors worked from the average income statement of an S&P 1500 company and found that a 1 percent price rise, with volume unchanged, would lift operating profit by 8 percent. That was more than three times the effect of a 1 percent rise in volume. Treat that figure as an average for large US firms, not a rule for your business. Work it out from your own margins: the thinner the margin, the more a small price change matters. ## Fixed versus variable costs Variable costs move with each unit you sell: materials, packaging, delivery, payment fees, sales commission. Fixed costs stay the same over a range of activity: rent, salaried staff, software subscriptions, insurance. Fixed costs often rise in steps, for example when you need a second warehouse. The split matters because of contribution margin. As [Wikipedia's entry on contribution margin](https://en.wikipedia.org/wiki/Contribution_margin) sets out, unit contribution is the selling price minus the unit variable cost. It is what each sale adds towards covering fixed costs and then profit. From there, [cost-volume-profit analysis](https://en.wikipedia.org/wiki/Cost%E2%80%93volume%E2%80%93profit_analysis) gives the break-even volume: fixed costs divided by unit contribution. Two cautions. First, the classic model assumes costs behave in a straight line within a relevant range and that each cost can be cleanly labelled fixed or variable. Real costs are messier, so agree the labels with the finance team before you calculate anything. Second, a product with positive contribution may be worth keeping even if it shows a loss after shared overheads, because cutting it removes its contribution but not the overheads. ## How consultants work a profit decline - **Pin down the question.** How much has profit fallen, over what period, and measured how? Agree the target too. "Restore last year's margin within 12 months" gives the work an end point. - **Check whether it's you or the market.** Compare the trend with competitors and the wider sector. If everyone is down, the answer probably lies in demand or input costs. If only you are down, look inside. - **Split revenue and costs.** Did revenue fall, costs rise, or both? Put a number on each. - **Quantify the four branches.** Break the change into price, volume, variable cost and fixed cost effects, as in the worked example below. - **Dig into the biggest branch.** Go one or two levels down in the branch that explains most of the change. Here you switch from arithmetic to interviews, customer data and operational reports to find the cause behind the number. - **Size the options.** For each fix, estimate the profit effect, cost and time to deliver. Recommend the few that close most of the gap. Form a hypothesis at step three or four, such as "discounting has eroded our average price," and let the data confirm or kill it. That keeps the work focused without locking you into an answer. ## An example (illustration only) An online tea retailer made £200,000 operating profit last year. This year it made £80,000. The founder's first reaction is "sales are fine, so it must be costs." The numbers say otherwise. ItemLast yearThis year Orders100,000104,000 Average price per order£30.00£29.00 Revenue£3,000,000£3,016,000 Variable cost per order£18.00£18.50 Variable costs£1,800,000£1,924,000 Fixed costs£1,000,000£1,012,000 Operating profit£200,000£80,000 Now split the £120,000 fall into the four branches: BranchCalculationEffect on profit Price£1.00 lower price × 104,000 orders−£104,000 Volume4,000 extra orders × last year's £12 contribution+£48,000 Variable cost£0.50 higher cost × 104,000 orders−£52,000 Fixed costHigher software and rent−£12,000 Total−£120,000 Revenue went up, yet price is the biggest problem. Going down the price branch, the team would ask whether the £1 drop came from discount codes, a shift towards smaller packs, or a deliberate price cut. Variable cost is the second lead: is it packaging, courier rates or product cost? Fixed costs barely matter here, so cutting the office budget would be effort spent in the wrong place. ## Common mistakes - Stopping at revenue. Flat or rising revenue can hide a price fall that volume growth happens to cover. - Leaving the tree generic. "Price, volume, fixed, variable" is only the start. Name the branches in the business's own terms, such as courier cost or average basket. - Ignoring mix. Averages shift when customers move between products, even if no single price changed. - Labelling costs by habit. Staff costs can be fixed in one business and variable in another, for example agency pickers paid per shift. - Jumping to cost cuts. Cutting is visible and feels decisive, but it may not touch the branch that moved. - Skipping the market check. If the whole sector fell, internal fixes can only do so much. ## When to use it, and when not to Use the profit tree whenever the question is about money made: a profit fall, a margin squeeze, a rise in costs, or a comparison of two plans. It also works as a planning tool, because every growth idea has to pull on at least one of the four branches. It is less useful on its own for questions that aren't about current profit, such as whether to enter a new market or buy a company. Those need their own structure, though the profit tree usually reappears inside them when you estimate the payoff.