The 87% that never existed
Every sales-training company on earth will tell you reps forget 87% of what they learn within a month. We went looking for the study. There isn't one.
Start with the number everybody knows.
"87% of sales training is forgotten within 30 days." You have seen it on a slide. You have probably said it. It appears in vendor decks, LinkedIn posts, conference keynotes, and — we are embarrassed to admit — in the first draft of our own pitch.
We went looking for the study behind it.
There is no study. The trail runs from one vendor's blog to another vendor's blog, each citing the other, occasionally gesturing at "research by Xerox" or "Sales Performance International" — with no publication, no sample size, no year, no methodology, and no document that anyone can produce. The same is true of its cousins: 84% lost after 90 days, reps forget 70% in a week, buyers only remember 10% of what you say. Every one of them is folklore wearing a lab coat.
This matters more than pedantry. If you are going to spend real money changing how your team sells, the first thing you should demand is that the people taking the money can source their claims. So here is what is actually known.
What is real: the curve
The forgetting curve itself is real, and it is old. Hermann Ebbinghaus described it in 1885, testing himself on nonsense syllables and measuring how much effort it took to relearn them later. His retention fell from 58.2% after twenty minutes to 21.1% after thirty-one days.
That is one man memorising gibberish in the nineteenth century. It is a beautiful piece of science and a terrible basis for a claim about your sales floor.
The honest modern citation is Murre and Dros (2015), published in PLOS ONE, who replicated Ebbinghaus properly — roughly seventy hours of learning and relearning over seventy-five days. The curve held: 47.2% retained after twenty minutes, 23.0% after two days, 4.1% after a month. They also found a small upward bump at around twenty-four hours, consistent with sleep consolidating memory.
Still one subject. Still nonsense syllables. What it establishes is the shape of forgetting, not a percentage you can bill against.
The most useful thing we found was Will Thalheimer's review of the forgetting literature, which went through 69 experimental conditions covering more than a thousand learners. His finding: forgetting ranged from 0% to 94%, depending entirely on the material, the context, and whether the learner ever used the thing again. Even within a day or two, the range ran from nothing to 73%.
Which means the truthful sentence is this:
Nobody can tell you what percentage of your sales training will be forgotten. Anyone who names a precise figure is guessing, and the fact that they named one tells you something about how they treat evidence.
What is also real: what works instead
If you cannot say how much is lost, you can still say a great deal about what stops the loss. Here the evidence is genuinely strong, peer-reviewed, and boringly consistent.
Spacing. Cepeda and colleagues (2006) meta-analysed 839 assessments across 317 experiments. Practice distributed over time beats the same practice crammed into one block, reliably — and the longer you need to remember something, the wider the gaps should be. A two-day workshop is, structurally, a cram.
Retrieval, not review. Roediger and Karpicke (2006) had students either restudy material or be tested on it. Restudying wins if you measure five minutes later. Testing wins decisively at two days and at a week. Being made to produce the thing — out loud, from memory, under mild pressure — is what fixes it.
Read those two findings next to each other and the implication for a sales floor is not subtle. Re-presenting the deck does nothing. Making a rep run the call again, on Tuesday, and again on Thursday, and again the week after, with someone stopping them when they slide back into old habits — that is the intervention the literature actually supports.
Where we stop short
We could tell you that coaching lifts quota attainment by 21.3%. CSO Insights reported exactly that in their 2016 study, alongside a 19% lift in win rates for organisations with formal coaching. It is the number our industry loves.
But it is a cross-sectional survey, published by a firm that sells sales enablement, and it shows a correlation: companies that coach formally also hit quota more often. It does not show that coaching caused it. High-performing sales organisations do a lot of things that struggling ones do not, and formal coaching is as likely to be a symptom of a well-run floor as a cause of one.
The peer-reviewed literature on sales coaching is thinner than anyone would like — mostly surveys with self-reported performance, very few field experiments. We would rather tell you that than dress it up.
And one more piece of honesty, because it cuts against us. The deliberate-practice literature — the "10,000 hours" story — has been substantially qualified. Macnamara, Hambrick and Oswald's meta-analysis (2014) found that deliberate practice explains about 26% of the variance in games, 21% in music, and less than 1% in professions. Structured practice will make a seller better than they were. It will not manufacture a great one, and we are not going to pretend otherwise.
What we actually believe
Strip out the folklore and what remains is a modest, defensible claim:
A one-off training event teaches people something they will mostly lose, because nothing in its design makes them retrieve it under pressure, spaced out over time, in the situation where it matters. Not because of a magic 87%. Because that is what memory does with anything you learn once and never use again.
Clario is built on the boring version of the evidence, not the exciting version of the statistic. We come in and teach the method. Then the coach makes every rep retrieve it — daily, in a live practice call, with someone telling them the moment they slip. The level moves because the behaviour moves.
If we ever quote you a number, you should be able to click it. That is the whole standard.