Why 'we cut onboarding time 34%' beats 'we're the best' every time
The psychology of why precise, checkable numbers read as more credible than generic superlatives — and how it changes what a cold email should actually claim.
By David Lara, Founder
Founder-reviewed ·How we research and correct articles
A cold email that says “we’re the industry leader” and one that says “we cut onboarding time from 11 days to 7” are making the same underlying pitch — this product is good — in two completely different registers. Only one of them is checkable. That difference isn’t a stylistic preference. It maps onto real, measurable psychology about which kinds of claims people actually believe, and it’s worth understanding why before you write the next line of outreach copy.
Precision signals effort, and readers can tell
The clearest experimental evidence comes from negotiation research, not marketing. Loschelder, Stuppi, and Trötschel’s 2014 study tested how people respond to a first offer stated as a round number (say, €15,000) versus a precise one (€14,875). The precise number consistently anchored harder — counteroffers landed closer to it, because recipients inferred that a specific, oddly exact figure implied the other side had actually done the math, not picked a comfortable round figure out of the air. A round number reads as a guess. A precise one reads as a calculation, and people update their own estimate toward calculations more than they update toward guesses.
This generalizes further than pricing. The mechanism the researchers describe — precision as a signal that real work happened — is exactly what separates “we’re the best in the industry” from “62% of our customers see a reply within the first week.” The first is a stance anyone could type without evidence. The second implies someone measured something, which is a specific, falsifiable claim a skeptical reader can choose to believe or doubt, but can’t dismiss as pure marketing reflex the way a superlative gets dismissed.
Vague language is also a measurable marker of deception
A separate, independent line of research gets at the same conclusion from the opposite direction. A Tilburg University analysis of linguistic concreteness compared how concrete versus abstract the language was across datasets of known-true and known-false statements — hotel reviews, stated future plans, that kind of paired truthful/deceptive text. The consistent pattern: less concrete, more generalized, more abstract language shows up disproportionately in the deceptive statements. The paper is careful to note this isn’t a lie detector — concreteness is a correlated signal, not proof, and the relationship depends on context. But it points at something people seem to track, even if only half-consciously: vague language is what you reach for when you don’t have (or don’t want to commit to) a specific, checkable fact.
Put the two findings together and there’s a coherent story: specific, precise claims read as credible because they imply real calculation happened, and because vagueness is exactly the pattern people (unconsciously) associate with a claim that wouldn’t survive being checked. Superlatives — “best,” “leading,” “world-class,” “cutting-edge” — fail on both counts simultaneously. They imply no measurement, and they happen to be the exact register of language that correlates with statements nobody bothered to make true.
Why this matters more in a cold email than almost anywhere else
Every reader of a cold email is, by default, running a low-grade skepticism filter — they didn’t ask for the message, they don’t know the sender, and unsolicited claims of quality are the oldest trick in selling. That’s precisely the environment where the credibility gap between a specific claim and a superlative is largest, because the reader has almost no other information to update on. There’s no in-person rapport, no shared history, no tone of voice — just the words on the screen, and whether those words sound like they came from measurement or from a template. A generic superlative in that context doesn’t just fail to persuade; it actively signals “this was written to be sent to thousands of people,” which is close to a confession that the email wasn’t personalized at all.
Why superlatives survived this long anyway
If the research is this consistent, it’s worth asking why cold email is still full of “best-in-class” and “industry-leading.” Part of the answer is that superlatives are cheap to write and specific claims aren’t — a real number requires you to have actually measured something, tracked a result, or done the comparison, while a superlative requires only confidence. Part of it is imitation: once enough senders in a category use the same three adjectives, using them back starts to feel like table stakes rather than a choice, even though the research says they’re close to costless to the reader’s belief. And part of it is a misdiagnosis of the goal — writers reach for superlatives because they want the email to sound impressive, when the research says what actually earns belief is the opposite instinct: sounding like someone who measured, not someone who’s impressed with themselves.
| Superlative | Specific claim | |
|---|---|---|
| Quality claim | "Best-in-class support" | "Median first response time: 4 minutes" |
| Scale claim | "Trusted by hundreds of companies" | "212 teams sending through us this quarter" |
| Outcome claim | "Proven results" | "Cut average onboarding from 11 days to 7" |
| Implies real measurement happened? | — | ✓ |
| Survives "how do you know that?" | — | ✓ |
Turning this into an actual editing rule
The practical version of both studies is a simple substitution test, and it applies to almost every claim a cold email makes:
- Replace “the best” with the actual number or comparison that made you believe it’s the best.
- Replace “industry-leading” with what, specifically, leads — faster by how much, cheaper by how much, more accurate by how much.
- Replace “trusted by many companies” with a real, nameable count or a specific, relevant logo — “trusted by many” is precisely the round-number-equivalent of a claim; a real figure is the precise one.
- Replace “cutting-edge technology” with what the technology actually does differently, stated plainly enough that a skeptical reader could picture it.
If a claim can’t survive that substitution — if there’s no real number, comparison, or specific mechanism behind the superlative — that’s useful information too. It usually means the claim shouldn’t be in the email at all, rather than that it needs a better adjective. A cold email with one fewer, more specific claim beats one with three unverifiable ones, because the reader who replies to a cold email is doing so based on what they believed while reading it, not on how many positive-sounding words it contained.
Specificity has a size limit too
One caveat worth being honest about, because both studies above have one: precision only helps up to a point. The negotiation research found precise numbers boost credibility because they imply real calculation — which means an implausibly precise claim (a suspiciously exact percentage with no source, or a number so oddly specific it reads as invented for effect) can backfire the same way a fake urgency claim does. The goal isn’t maximum decimal places. It’s a claim specific enough that a skeptical reader believes someone actually measured it, and honest enough to survive them asking how.
How Norbelys makes the specific version easier to write and prove
Specificity is easy to say and hard to sustain across hundreds of sends by hand — which is exactly the gap Norbelys is built to close. Norbe, the built-in AI operator, drafts copy grounded in the actual recipient’s company and context rather than generic template language, so the specific detail in a first line is real instead of a best guess at plausible personalization. And because only human-verified opens and replies count in Norbelys’ analytics — not every tracking-pixel fire — the numbers you’d want to put in your own next cold email (a real reply rate, a real time-to-first-response) are numbers you can actually stand behind, not inflated ones that collapse under a skeptical read the same way a hollow superlative does. You can also A/B test a specific claim against a generic one directly on your own list, rather than taking a psychology study’s word for which one wins with your actual audience.
The negotiation research and the deception research arrive at the same place from two different directions: specificity reads as truth, and vagueness reads as evasion, whether or not either one actually is. Write the version of your pitch that survives being checked — start sending it with Norbelys and see whether the specific number outperforms the confident adjective.
Specific claims vs. superlatives, quickly
Isn't a specific number just as easy to fake as a superlative?
Technically yes, but the research on deceptive language suggests people don't write fabricated specifics as readily as they reach for vague superlatives — precise, checkable claims carry more perceived risk if they're wrong, which is part of why they read as more credible in the first place. The real safeguard isn't picking a more convincing-sounding number; it's only using specific claims you can actually back up if a reader asks, which is the whole point of using them.
Does this mean I should never use words like 'leading' or 'best' in a cold email?
Not as an absolute rule, but treat every superlative as a placeholder that needs a real claim behind it before the email ships. If you can immediately follow 'industry-leading' with the specific number or comparison that justifies it, keep both. If you can't, the research suggests the superlative alone is doing less work than it feels like it's doing, and cutting it is rarely a loss.
What if I genuinely don't have an impressive number yet?
A smaller, honest specific claim consistently outperforms a big, vague one — 'we've sent our first 5,000 emails and kept a 0% spam-complaint rate' is more credible than 'the best deliverability in the business' with no company behind it yet. Specificity is about precision, not scale; a modest real number still signals real measurement, which is the mechanism the research says actually earns belief.