Most voice guides are adjectives nobody can apply. The only published standards for clear writing are functional, not numeric, and one of them is enforceable.
A tone of voice guide made of adjectives cannot be applied, and cannot be checked. Confident, human, bold, approachable: every company in your category has claimed all four, and no writer facing a blank page has ever been helped by them.
What can be applied is a set of decisions about specific mechanics, and what can be checked is whether the reader understood. Both of those exist in published form, written by an institution with no interest in brand strategy: the US federal government, which was required by statute to write clearly and produced guidance on how.
That guidance is worth reading precisely because it is not marketing advice. It names techniques, refuses to name a score, and tells you to test instead.
The statutory definition, and what it deliberately omits
The 2010 statute requiring federal agencies to write plainly is a useful starting point, mostly for what it does not contain.
The purpose, in the law’s own words. To improve accountability “by promoting clear Government communication that the public can understand and use.”
And the definition of the thing itself. Plain writing means “writing that is clear, concise, well-organized, and follows other best practices appropriate to the subject or field and intended audience.”
Notice what is absent. No reading level. No sentence length. No word count. No readability score. The standard is entirely functional and audience-relative, which is inconvenient for anyone who wanted a number to put in a brand guideline.
Two boundaries worth stating honestly. The Act binds federal agencies, not companies, and it explicitly excludes regulations from its scope. Nothing here is a legal obligation on your marketing. It is the most rigorously developed public guidance available, which is a different and still useful thing.
One practical note. The guidance formerly published at its own domain now redirects to a general government digital guides site. If your brand guidelines cite the old URL, the link works but the destination has changed.
Where the statute is abstract, the accompanying guidelines are specific, and twice they say which change matters most.
On voice, with an unusually strong claim. “Passive voice obscures who is responsible for what and is one of the biggest problems with government documents.” And then: “More than any other writing technique, using active voice and specifying who is performing an action will change the character of your writing.”
On sentence length, with a rule rather than a target. “Express only one idea in each sentence.” The reasoning: “Sentences loaded with dependent clauses and exceptions confuse the audience by losing the main point in a forest of words.” And the summary line: “Complexity is the greatest enemy of clear communication.”
On vocabulary, borrowing a century-old formulation. “Prefer the familiar word to the far-fetched. Prefer the concrete word to the abstraction. Prefer the single word to the circumlocution. Prefer the short word to the long.”
On pronouns, with the second superlative claim. “More than any other single technique, using ‘you’ pulls users into your document and makes it relevant to them. When you use ‘you’ to address users, they are more likely to understand what their responsibility is.”
With a caveat most brand guides skip. “Be sure to define ‘you’ clearly.” In B2B, where a page may be read by a user, a buyer and a procurement officer, an undefined “you” produces text that addresses nobody.
And a structural instruction that changes more than it looks. “Address one person, not a group.” It is the difference between writing for a market and writing to a reader.
The most useful thing in the guidance is a refusal. Nowhere does it set a readability target, and it says what to do in place of one.
There is no prescribed grade level. Across the full document, no reading level and no readability formula is set as an objective. The standard remains “appropriate to the subject or field and intended audience.”
And the consumer protection regulator says the same thing in its own domain. “There is no set formula for a clear and conspicuous disclosure; it depends on the information that must be provided and the nature of the advertisement.”
What the guidance recommends instead is testing, in three named forms. Paraphrase testing, usability testing, and controlled comparative studies, the last defined as: “Collect quantitative data on how well the general public uses your final document.”
Paraphrase testing is the one worth stealing. Give someone the paragraph, ask them to say back what it means in their own words, and listen for the part they cannot restate. It requires no tooling, five people, and half an hour.
Which reframes what a voice guide should contain. Not a target score, which no institution endorses, but a test the team can actually run before publishing.
One piece of context for why this matters in the US market. National assessment data records 28 percent of US adults performing at the lowest literacy level in 2023, up from 19 percent in 2017, with 44 percent at level 3 or above. Whatever your audience, writing that only works for confident readers is writing that works for fewer people than it did a few years ago.
There is one place in your writing where clarity is a regulated requirement rather than a brand choice, and the regulation is unusually specific about it.
The definition, from the rule itself. “‘Clear and conspicuous’ means that a disclosure is difficult to miss (i.e., easily noticeable) and easily understandable by ordinary consumers.”
With a channel-matching requirement. If the claim is made visually, the disclosure must appear “in at least the communication’s visual portion”; if audibly, in the audible portion; if both, in both. And “a disclosure presented simultaneously in both the visual and audible portions … is more likely to be clear and conspicuous.”
And a hard rule for anything interactive. “In any communication using an interactive electronic medium, such as social media or the internet, the disclosure should be unavoidable.”
The definition also redefines your audience for you. “When an endorsement targets a specific audience, such as older adults, ‘ordinary consumers’ includes members of that group.” Your reading of what is obvious is not the standard; theirs is.
The evaluation factors are published. Proximity to the claim, prominence, whether it is unavoidable, whether other elements distract from it, whether it needs repeating, adequate duration and cadence, and “whether the language of the disclosure is understandable to the intended audience.”
With a self-correcting instruction attached. “If there are indications that a significant proportion of reasonable consumers are not noticing or comprehending a necessary disclosure, the disclosure should be improved.”
And on vocabulary, guidance that reads like a tone of voice rule. Use “simple and clear language”. Do not “use vague or confusing terms like ‘sp,’ ‘spon,’ or ‘collab,’ or stand-alone terms like ‘thanks’ or ‘ambassador.’” Placement matters too: disclosures “are likely to be missed if they appear only on an ABOUT ME or profile page, at the end of posts or videos, or anywhere that requires a person to click MORE.”
Replace the adjectives with decisions somebody can apply at eleven at night without asking anyone.
Person and address. Who is “you”, named explicitly, and whether the company is “we” or its own name. Then hold it everywhere, including error messages and invoices.
Voice and tense. Active by default, with the actor named. Present tense unless the past is the point.
The sentence rule. One idea per sentence. Not a word limit, which produces choppy text, but a content limit, which produces clear text.
A word list with replacements, not prohibitions. Twenty terms your industry overuses, each with the plain alternative next to it. A list that only forbids is a list that gets ignored, because the writer still has to fill the gap.
The named moments where tone is decided. Pricing, an outage, a rejection, a renewal, a mistake you made. These are where a voice either exists or does not, and they are exactly the passages that never appear in the guide.
A worked example per moment. One paragraph written the wrong way and the same paragraph written the right way. Two examples teach more than two pages of principles.
And the test. Name paraphrase testing as the acceptance step for anything customer-facing, with five readers. A guide that ends with a check gets applied. A guide that ends with aspirations gets filed.
Take the last thing you published and run one pass: convert passive constructions to active with the actor named, split every sentence carrying two ideas, and check that “you” is defined somewhere on the page. That pass alone does most of what a voice guide is meant to do.
Then run a paraphrase test on the paragraph that matters most, with five people who are not in marketing. The sentence they cannot say back is the sentence to rewrite, and it is almost never the one you expected.
If anything you publish carries a claim that needs qualifying, treat the disclosure as regulated writing rather than fine print: near the claim, prominent, unavoidable, and phrased so the intended audience understands it without effort.
No official standard sets one. The Federal Plain Language Guidelines prescribe no grade level or readability formula, and the FTC states there is no set formula for a clear disclosure. Every published standard is functional: understandable to the intended audience.
What is the single highest-leverage writing change?
The federal guidelines name two. On voice: more than any other writing technique, using active voice and specifying who performs the action will change the character of your writing. On pronouns: more than any other single technique, using 'you' pulls users into your document.
When does tone stop being a preference?
When a claim requires a disclosure. Regulation defines clear and conspicuous as difficult to miss and easily understandable by ordinary consumers, and requires the disclosure to be unavoidable in interactive media.
How do you test whether writing is clear?
The federal guidelines recommend three methods rather than a score: paraphrase testing, usability testing, and controlled comparative studies collecting quantitative data on how well people actually use the document.