Business news loves a record result. A company doubles its profit, and the headline writes itself. But a single year, however impressive, is weak evidence about the business behind it.
One idea runs through Warren Buffett and the Interpretation of Financial Statements more than any other: consistency. The authors return to it in almost every chapter. High margins, low debt, modest capital needs and strong returns all matter, but only when they persist year after year.
This article explains why one year proves so little, what consistent performance looks like in the numbers, how to separate real earning power from one-off results, and why the same idea is one of the most useful tests a founder can apply to a new venture.
Why one year proves so little
A single year can be distorted by almost anything:
- a temporary shortage that lifts prices for everyone
- a large one-off contract that will not repeat
- the sale of a building or a division
- cost cuts that cannot be sustained, such as deferring maintenance or freezing marketing
- an insurance payout, legal settlement or government grant
- accounting changes, or a weak comparison year that makes growth look larger than it is
- a favourable movement in exchange rates or commodity prices
None of these says much about whether the business can earn the same next year, or in ten years. Some are entirely legitimate; they are simply not repeatable, and so they tell you little about the business’s underlying strength.
The comparison-year trap
Growth percentages deserve particular care. A business whose profit falls from $10 million to $4 million in a bad year, then recovers to $8 million, can report “100% profit growth” while still earning less than it did two years earlier. Headlines rarely mention the base. Always look at the absolute figures over several years, not just the change from last year.
What a durable business looks like over time
According to the book, businesses with a durable competitive advantage tend to show steady net earnings with an upward trend. Not necessarily smooth. Recessions and bad years happen. But the long-run line rises, and the bad years are shallow rather than catastrophic.
Businesses without an advantage tend to show a different shape: profits that swing between good years and losses, with no clear upward direction. Their earnings follow the cycle of their industry rather than any strength of their own.
The book’s suggested window is roughly ten years. That is long enough to include at least one downturn and to reveal whether a good run was structural or lucky.
An illustration
Here are two hypothetical businesses’ net earnings over ten years, in millions of dollars.
| Year | Business A | Business B |
|---|---|---|
| 1 | 5.0 | 4.0 |
| 2 | 5.4 | 9.0 |
| 3 | 5.9 | 2.0 |
| 4 | 5.6 | −3.0 |
| 5 | 6.3 | 6.0 |
| 6 | 6.9 | 12.0 |
| 7 | 7.4 | 1.0 |
| 8 | 7.2 | 5.0 |
| 9 | 8.0 | 11.0 |
| 10 | 8.7 | 3.0 |
| Total | 66.4 | 50.0 |
Business B had the single best year by far: $12 million in year 6. A reader who saw only that year would think it the stronger business. Over the decade, Business A earned a third more, grew in eight of ten years and never came close to a loss. Its two dips (years 4 and 8) were shallow. Business B’s results follow no pattern a planner could rely on.
Business A is the kind the book favours. Its consistency suggests something structural: customers who keep returning, costs under control, a position competitors cannot easily take.
Separating real earnings from one-off items
To see the real trend, strip out what will not repeat. The income statement and its notes usually show these items separately: gains or losses on asset sales, restructuring costs, impairments and write-downs, and similar.
The book is direct about this. A profit created by selling assets is not earning power. A business that sells a factory each year to report a profit is shrinking, not growing. Look at operating profit and recurring net earnings, and treat everything else as background.
Statutory and underlying profit
Many Australian listed companies report both a statutory profit, calculated under accounting standards, and an underlying or normalised profit that excludes items management considers unusual. Underlying figures can be helpful, but they are chosen by management, and management naturally prefers the more flattering version.
Read what has been excluded. If restructuring costs appear as “one-off” every year, they are part of the cost of running the business. A useful test is to add up all the excluded items over several years. If they consistently push in one direction, the underlying figure is overstating what the business really earns.
Other measures worth tracking for consistency
Net earnings are the headline, but consistency matters across the whole set of statements. Over ten years, it is worth looking for steadiness in:
- gross margin: stable margins suggest stable pricing power
- operating expenses as a share of gross profit: steady ratios suggest disciplined management
- return on equity: consistently strong returns without heavy borrowing
- earnings per share: rising steadily, not just jumping when shares are bought back
- operating cash flow: cash from operations tracking earnings, rather than lagging behind them
- debt levels: stable or falling rather than climbing year after year
A business that shows consistency across most of these is very different from one with a steady headline profit but erratic margins, rising debt and weak cash flow underneath.
Building a ten-year view
The practical method is simple, though it takes an afternoon. For a listed company, collect ten years of annual reports from the company’s investor pages or the ASX announcements platform. Many reports include a five-year summary, so two or three reports may cover the whole decade.
Set up a table with one column per year and rows for the measures that matter: revenue, gross margin, operating profit, one-off items, net earnings, earnings per share, operating cash flow, long-term debt and return on equity. Fill it in from the full financial statements rather than the summary presentation, which tends to emphasise the most favourable figures.
Then step back and look at the shape. Draw a simple line chart of net earnings and operating cash flow if it helps. A few questions usually reveal the story quickly:
- Does the line rise over the decade, or wander?
- How many years show a fall, and how large were the falls?
- Did one-off items appear regularly?
- Did cash flow keep pace with earnings?
For your own business, the same table can be built from your accounting system. Even three or four years of history, laid out side by side, show more than any single year’s report.
Consistency as evidence, not decoration
Why give consistency so much weight? Because it is very hard to fake across a decade. A single year can be managed, timed or flattered. Ten years of steady results, through different economic conditions, different managers and different competitors, is strong evidence of something structural.
This also connects to risk. A business whose earnings are consistent is far less likely to fail, which is why, in Buffett’s approach, consistency and safety are two sides of the same coin. It also makes the future easier to estimate. Nobody can predict next year’s results precisely, but a business with ten steady years gives a reasonable basis for expectations. A business whose results swing wildly gives almost none.
Consistency is not the same as no change
Consistent businesses are not static. They adjust prices, improve processes, enter new markets and refine products. What stays consistent is the underlying economics: customers keep valuing what they offer, and they keep earning a good return on it. In fact, the steadiness of their results often reflects constant, quiet improvement rather than standing still.
Consistency inside the business
Consistent results on the financial statements are usually the product of consistent work inside the business. The businesses that report steady earnings tend to share some habits: documented processes that produce the same quality every time, customer service that does not depend on who happens to answer the phone, purchasing and pricing disciplines that do not change with the mood of the month, and managers who measure the same things in the same way year after year.
This matters for owners because it points to where consistency can be built. Few businesses can control the economy, competitors or customer tastes. Every business can control whether its products and services are delivered reliably. Reliability earns repeat customers, repeat customers produce recurring revenue, and recurring revenue produces the steady line the book looks for.
When inconsistency is not a red flag
Not every volatile business is weak. Some industries are naturally cyclical: construction, mining, agriculture, tourism. A well-run business in such an industry may show strong results in good years and modest ones in bad years, while still outperforming its competitors across the whole cycle.
The useful comparison in these cases is relative: does this business hold up better than others in the same industry through the cycle? Does it stay profitable in downturns when competitors lose money? Consistency relative to peers can still reveal an advantage, even when absolute results move with the economy.
What this means for founders
New businesses do not have ten years of history. But the same idea guides early decisions.
Prefer revenue that recurs. Customers who buy repeatedly, subscribe, or rely on you as part of their routine create the consistency that one-off sales cannot. Even in project-based work, maintenance agreements, retainers and repeat clients smooth the line.
Be cautious about building around a temporary condition. A shortage, a fad, a regulatory change or a single large customer can make an idea look stronger than it is. Ask what happens when the condition passes.
Measure what repeats. When tracking progress, separate recurring results from one-time wins. It is easy to celebrate a big month that tells you little about the next one. A simple monthly report that shows recurring revenue separately from one-off revenue makes the real trend visible.
Value steady over spectacular. A product that sells reliably at a modest margin can be worth far more over time than one that sells spectacularly once.
Look at cohorts. Do customers who bought in month one still buy in month six? Retention by cohort is one of the clearest early signals of whether a business will become consistent.
In validation terms, consistency is the difference between proving that something can happen and proving that it keeps happening. Only the second is a business.
A worked example
A small business sells handmade furniture. This is an illustration.
In its second year, a feature in a popular magazine produces a surge of orders. Revenue triples for three months. The owner, encouraged, hires two more makers and signs a lease on a larger workshop.
By the end of the year, the surge has passed. Orders return roughly to their previous level, but the business now carries higher wages and rent. It spends the following year struggling.
Looking back, the owner separates the year’s results into recurring and one-off revenue. Recurring orders, from referrals, repeat customers and a steady trickle of online enquiries, had been growing at a modest, reliable rate. The magazine surge was a windfall. Had the owner planned around the recurring trend, the business would have added capacity gradually as that trend justified it.
The owner now reviews results quarterly, with one-off events shown separately, and makes commitments only on the strength of the recurring line.
Common mistakes
Judging by the best year. It is the least representative.
Trusting percentage growth without the base. Recoveries from a bad year look like growth.
Accepting underlying profit without reading the adjustments. Repeated “one-off” costs are recurring costs.
Expanding on the strength of a windfall. Commitments outlast surges.
Treating cyclical results as failure. Compare with peers across the cycle.
Questions to ask
- What did earnings look like over the last ten years, not just the last one?
- How deep were the bad years, and how quickly did results recover?
- Which items in recent results will not repeat?
- Are margins, returns and cash flow as steady as the headline profit?
- For your own business: how much of this month’s revenue would you expect to see again next month?
Bringing it together
A single great year is a story. Ten consistent years are evidence. The book’s emphasis on consistency is its most practical lesson: it protects readers from being dazzled by headline results and directs attention to what a business earns reliably, year after year.
For founders, the same discipline applies from the start. Build revenue that recurs, separate windfalls from the trend, and make commitments on the strength of what keeps happening rather than what happened once.
Source: Mary Buffett and David Clark, Warren Buffett and the Interpretation of Financial Statements (2008). Figures in this article are illustrations, not data. This article is general information, not financial or investment advice.
