Forgetting curve: why sales training won't stick

A classic sales training looks like this: a day or two in a conference room, lots of content, high energy, glowing evaluations on the way out. Six weeks later it is hard to find any trace of it in how the reps actually sell. That is not a sign of bad training. It is exactly what memory research predicts when you teach something once and never top it up.

It is worth understanding the mechanism before we talk about the fix, because the fix becomes obvious the moment you see how forgetting works. And it contradicts almost everything about how companies normally buy and deliver training.

What is the forgetting curve, really?

In 1885 Hermann Ebbinghaus ran a self-experiment in which he learned lists of nonsense syllables and measured how much he retained after different intervals. The pattern he found has held ever since: memory falls steeply soon after learning and then flattens. Most of what is going to be lost goes early. Do not quote me exact percentages here, because the popular figures about how much you forget in an hour or a week are popularizations. What is robust is the shape of the curve: steep first, flat later.

That this is not just a 19th-century curiosity was confirmed in 2015. Jaap Murre and Joeri Dros replicated Ebbinghaus' original experiment and published the result in PLOS ONE. The curve held. So when you run a full day in June as a sales leader and hope it sticks through September, you are working against one of the most replicated findings in cognitive science. This applies to sales training exactly the way it applies to syllables and vocabulary.

Is it true that 87% of sales training is forgotten?

You have probably seen the number: 84 to 87 percent of all sales training is gone within 30 to 90 days. It shows up in almost every pitch for a training tool, including tools in our own corner of the market. The problem is that it has no primary source. It is attributed sometimes to Xerox, sometimes to Sales Performance International, with different figures depending on who is citing it, and nobody can point to the study behind it. It is a zombie stat: it survives because it sounds right, not because anyone measured it.

We are only including it to kill it. You do not need an invented percentage to get the point, because the real research says the same thing without making up exact numbers. Ebbinghaus and the Murre and Dros replication show that a large share goes early and the curve then flattens. That is enough. When someone sells you a tool with a precise 87 percent, ask for the study. There isn't one.

Why does the one-off workshop fail so badly?

The one-off workshop is massed learning: everything packed into a single sitting. The brain is not built to hold on to something it sees once and then never again. A skill that is not reactivated lands on the steep part of the curve and thins out before the rep has used it in a real deal. You pay for a full day of content and then pay again, invisibly, as most of it leaks out over the following weeks.

This is where Salesprep does something other than a workshop. Instead of one sitting, the training is broken into short AI roleplays spread across the weeks, and after each call the rep gets ten concrete scores on opening, questions, objections and the close. The skill is reactivated before it can fade, and the feedback points to exactly what the next session should drill. That is the difference between teaching a thing once and keeping it alive.

How does spaced repetition make knowledge stick?

Spaced repetition, or distributed practice, means spreading review across time instead of cramming it into one go. Each time you pull a skill back just before it starts to fall out of memory, the curve flattens a little more and holds longer until next time. This is not one theory among many. In 2006 Cepeda, Pashler, Vul, Wixted and Rohrer reviewed 839 assessments across 317 experiments and found that spaced practice reliably beats massed practice. It is one of the most stable findings in all of learning research.

Translated to sales training, that means five short sessions spread over five weeks beat one full day, even when the total time is the same or less. It is not intuitive, because a full day feels more like real training. But the feeling of having learned and actual retained skill are two different things, and it is the second one that shows up in the pipeline.

How to build training that resists the forgetting curve

The practice follows from the research. Replace the single workshop with a rhythm:

• Short sessions, often. Ten to twenty minutes of focused practice several times a week beats a rare full day, because each session reactivates the skill before it falls.
• Increasing intervals. Review closely together at first, then space out, so you drill each piece right as it is about to fade from memory.
• Retrieval, not rereading. Actively running a call sticks harder than listening to the same briefing again. The practice should feel like a test, not a replay.
• Measurement every time. Without feedback you do not know whether the session moved anything. Concrete scores point out which variable the next session should grab.

This is the same logic we went through in our piece on deliberate practice, but seen from the other side. That piece is about how you make a single drill sharp. This one is about how you distribute the drills across time so they do not drain away. You need both. A perfectly designed session run once still gets forgotten.

Stop buying training as an event and start running it as a habit. In Salesprep, sales training becomes spaced, repeated roleplays where each session has a goal and ten scores, so the curve flattens week by week instead of falling after the conference room. It is not more content. It is the same content, placed where memory can actually hold on to it.