A sales rep sits through a two-day workshop. Gartner’s research on training retention found that sellers forget 70% of what they were taught within a week, and 87% within a month, which means the workshop is largely gone from memory before the next full workweek is over.
A 1984 study found a fix for that forgetting curve, decades before most sales training programs existed, and the fix never made it into how sales training gets designed.
Sales reps forget 70% of training content within one week and 87% within a month, per Gartner, and the research explaining why traces back to Benjamin Bloom’s 1984 study finding that one-on-one coaching outperforms classroom instruction by two full standard deviations. The average coached learner in Bloom’s study outperformed 98% of learners taught in a conventional classroom, which means the fix for the forgetting curve has been documented since 1984 and most sales training still isn’t built around it.
The Researcher Who Built L&D’s Favorite Framework Also Disproved Its Delivery Model
Bloom’s Taxonomy is on the wall of nearly every corporate training room: remember, understand, apply, analyze, evaluate, create. It’s the foundation of most certification programs on the market. Fewer people know that the same researcher, Benjamin Bloom, published a second paper that undercuts how most of those programs get delivered.
In 1984, Bloom published “The 2 Sigma Problem” in Educational Researcher, comparing three instructional conditions: conventional classroom teaching, mastery learning with structured feedback and correction, and one-on-one tutoring combined with mastery learning.
| Instructional Method (Bloom, 1984) | Result vs. Conventional Classroom |
|---|---|
| Conventional classroom teaching | Baseline |
| Mastery learning with feedback and correction, no tutor | +1 standard deviation |
| One-on-one tutoring combined with mastery learning | +2 standard deviations; average tutored student outperformed 98% of the classroom group |
The average student who received one-on-one coaching on top of mastery learning performed two full standard deviations above the average student taught in a classroom. In plain terms, that student outperformed 98 out of 100 classroom-taught peers, and the effect held for the average student, including the ones who were never going to be the top performer in the room.
Why Bloom Called the Finding a Problem
Bloom called his own finding a problem because he couldn’t solve the part that mattered for scale. One-on-one tutoring for every student was too expensive to run broadly. Whether the method worked was settled by his own data. The open question was how to get the same result without a tutor sitting next to every learner.
Sales enablement adopted Bloom’s Taxonomy for curriculum design and never circled back to his coaching finding. The framework that organizes what a training program teaches came from Bloom. The framework that explains why that training fails to stick also came from Bloom, published sixteen years later, and it got filed away as an academic curiosity instead of a design requirement.
What Happens Between the Training and the Forgetting
A separate line of research explains the mechanism behind the effect, not just its size. Robert Brinkerhoff, a researcher at Western Michigan University, spent his career studying why training works for some people and not others. His finding: only about 15% of training participants make a sustained change in behavior after a learning experience at work. The other 85% either never try to apply what they learned, or try once, hit friction, and revert to their old approach.
What separated the 15% from the 85% was what happened after the session ended. The 15% who succeeded had a manager who reinforced the material, a chance to practice it in a real situation, and feedback when they got it wrong. The 85% who didn’t walked back to their desks, and the world moved on without anyone checking whether their behavior had changed.
What This Means for a Sales Training Budget
Put Gartner’s forgetting-curve data next to Bloom’s and Brinkerhoff’s findings and the pattern is consistent across all three: a classroom session, a workshop, or a certification course sits at the bottom of what the research shows works, and one-on-one coaching paired with structured practice sits at the top, by a margin wide enough to move the average learner past 98% of their classroom peers. Most sales training budgets are still allocated in the opposite order, with the largest share going to content design and delivery and the smallest share going to manager-led coaching after the session ends.
The distinction this research draws, developed at length in Gap Revenue Performance, is between training as a single event and training as the first step inside a system that keeps reinforcing it. A workshop with no coaching or repeated practice afterward is the exact condition Bloom’s study measured as weakest, and Gartner’s forgetting-curve numbers describe what that condition produces on a live sales team.
The same reversion pattern shows up wherever a team measures rep behavior thirty, sixty, and ninety days after a rollout instead of stopping the count on graduation day.
Frequently Asked Questions
What percentage of sales training do reps forget, and how fast?
Per Gartner’s research on training retention, sellers forget 70% of what they were taught within one week of a training session, and 87% within one month. The forgetting is fast enough that a two-day workshop has largely faded from memory by the following Monday.
What is Bloom’s 2 Sigma Problem and why does it matter for sales training?
Benjamin Bloom’s 1984 study, published in Educational Researcher, compared conventional classroom instruction, mastery learning, and one-on-one tutoring combined with mastery learning. The combination of tutoring and mastery learning produced results two full standard deviations above the classroom group, meaning the average tutored student outperformed 98% of students taught in a classroom. Applied to sales, it means one-on-one coaching after a training session produces a measurably larger, well-documented performance gain than the training session by itself.
Why didn’t sales enablement adopt Bloom’s coaching research if it’s been available since 1984?
Bloom called his own finding “the 2 Sigma Problem” because one-on-one tutoring for every learner was too expensive to scale; the result itself was already settled by his data. Sales enablement adopted Bloom’s Taxonomy for organizing curriculum content but never built delivery models around his coaching finding, which requires ongoing manager involvement rather than a one-time content investment.
What percentage of employees apply what they learn in training?
Robert Brinkerhoff’s research found that only about 15% of training participants make a sustained change in their behavior after a training session. The remaining 85% either never attempt to apply what they learned or try once, struggle, and revert to their previous approach, with the difference driven by whether a manager reinforced the material and created chances to practice it afterward.
What determines whether sales training sticks?
Across Bloom’s and Brinkerhoff’s research, the determining factor is what happens after the training session ends. Reps who get manager reinforcement, real-deal practice, and feedback on what they got wrong retain and apply the material. Reps who complete a session and return to normal work with no follow-up default back to prior behavior within days, consistent with Gartner’s forgetting-curve data.
How should a sales training budget change based on this research?
The research points toward shifting spend away from content design and delivery alone and toward manager-led coaching and structured practice after a session, since that is the condition Bloom’s study measured as producing the largest, most durable performance gain. A training budget built entirely around workshops and certification content is optimized for the weakest-performing condition in the research.
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