Numbers in Copy: Claims You Can Stand Behind
Every number in copy is a claim with a source, a date and a scope, or it should not be there. This guide covers customer counts, results, ratings and comparisons, and how to write figures as honest dated snapshots.
The short answer
Treat every number in your copy as a claim you may be asked to prove: a count of customers, a result, a saving, a rating, a timescale, a comparison. For each one, know the source it came from, the date it was true, and the scope it covers, and write the number so its scope is visible to the reader. Round honestly rather than implying precision you do not have, update or retire figures as they age, and never present an illustration, a sample or a single customer outcome as if it were a measured average. Where a figure comes from a published external source, name the source beside it, as this site does with the sources listed below each guide.
The kinds of numbers, and their risks
Counts grow stale quietly: customers served, products sold, years in business. Results carry the highest risk, because a reader reasonably takes them as a prediction about their own case. Ratings and review averages are arithmetic over a real set and must match that set wherever they appear, as covered in displaying reviews. Savings and comparisons depend on the comparison basis: against what price, whose product, measured when. Timescales depend on conditions. Each kind fails differently, so the audit in this guide goes kind by kind rather than treating numbers as one problem. The common rule is scope: a true number with its scope hidden can mislead as surely as a false one.
Illustrations must be labelled as illustrations
Worked examples help readers understand an offer: what a typical order might contain, how a saving is calculated, what a process timeline can look like. They become claims the moment a reader could reasonably take them as measurements. Label them in the text itself, starting the passage with Illustration: or making the example status unmistakable in its wording, and use round numbers so the example does not borrow the authority of measurement. Never let an illustration travel: if it is quoted in an advertisement, a headline or a summary, the label travels with it, or the illustration does not go. This rule protects good examples, because readers who trust your labels will trust your real figures too.
Write volatile figures as dated snapshots
Ratings, prices, counts and rankings move. A figure that was true when written becomes a small falsehood by standing still. The practical convention is to date the claim in the copy: as checked in a named month and year, or with the period the count covers stated plainly. Then put the figure on a review rhythm with your other proof, updating the number and its date together. A dated figure is not weaker than an undated one. It reads as maintained, and it stays honest as time passes, because the reader can see exactly what is being claimed: this was the state, at that time, from that source.
External figures need their source beside them
When you quote research or a market figure, name the publisher in the sentence or directly beside it, and keep the claim to what that source actually supports. Do not lift a striking figure from a secondary article without checking the original, do not drop the qualifiers the original attached, and do not use an industry average as if it described your customers. If a source is old, contested or based on a population unlike yours, either say so or choose not to use it. The point of citing a source is that a reader could follow it. A citation that would embarrass you if followed is worse than no citation.
What must never be invented
Never invent a customer count, a review average, a number of units sold, a percentage improvement, a typical saving or a survey result, and never present a target, a hope or a supplier claim about their product as your measured experience. Do not create a precise-looking figure by estimating quietly and keeping the decimal places. If the business does not yet have the figure, the copy has honest alternatives: describe the process, quote a real testimonial with consent, state the guarantee, or say plainly that the business is new and what it offers instead. Those alternatives are the replacements set out in fake proof and trust mistakes, applied to numbers.
The number audit
Once or twice a year, extract every number from your key pages into a list with four columns: the figure, its source, the date it was last verified, and where it appears. Verify each against its source, update or remove as needed, and check that the same figure agrees everywhere it appears, including advertisements, profiles and email templates that copywriters may have lifted from the site. Numbers drift between surfaces exactly as addresses do. Keep the completed list with your proof audit from the trust cluster. Together they form the record that every quantitative claim on the site was, at a known date, a claim the business could stand behind in public.
Sources and evidence on the record
- US Federal Trade Commission, advertising and marketing guidance - the honesty rules for claims, reviews, endorsements and disclosures.
- Baymard Institute, research blog - published findings from its checkout and product-page usability studies.
- CXL, CXL blog - practitioner writing on testing method, research process and optimisation programme discipline.
Evidence basis: Research-led guide. Figures are attributed to the published sources listed below and carry their check date; the method sections are the desk's, the numbers are the sources'. Applies when: Any copy that states a count, result, rating, saving, timescale or comparison