Repetition Retention Rate: a mental model for communication

September 20, 2020

A mental model is an explanation of someone’s thought process about how something works in the real world. It is a representation of the surrounding world, the relationships between its various parts and a person’s intuitive perception about his or her own acts and their consequences. Source

All models are wrong and some are useful. -George E. P. Box

While working through a project, I found myself getting frustrated that — although I and my immediate team knew aware of all the recent events and decisions — many other people were (seemingly inexplicably) unaware of what was going on. This prompted me to develop this mental model for communication.

The Model

A piece of information must be repeated a certain number of times for all people before it is retained. The number repetitions is a constant; the variable is the frequency with which the repetitions happen in order for retention to occur.

In Other Words…

In order to retain information, people need to hear the same thing multiple times. While there is some variation in how many times, given the “warmth” of the receiver of information, generally speaking, the same piece of information will take the same number of repetitions to be retained for all people. The discrepancy in time to retention should be attributed the frequency of repetitions rather than time itself.

An Example

Let’s take a piece of information — say the name of a vendor “Vendor X” — requires 10 repetitions to retain. The people on the project who are the closest to the vendor will rack up those 10 times very quickly — maybe they do the initial research and see the name 3 times on their website, then again twice during email exchanges, another 3 times while setting up a meeting, hear it said 2 times more on an initial call, and by the time the recap email is sent, it’s learned information: Vendor X’s name sticks.

However, if you’re in an adjacent department or an executive, you only hear the vendor’s name once or maybe twice a week. It will take you somewhere between 5-10 weeks to fully retain that information on the vendor and what they do.

In both cases, it took 10 repetitions for the name to be retained. While it is accurate to say that it took the project team 3 days to remember what took the executive 5 weeks to retain, the true differentiator was not time passed: it was the speed between repetitions.

Aside from it being generally good business to remember your vendors names, it is also important to recognize the downstream impacts of knowing or not knowing this information. If I run into issues with Vendor X, and I am attempting to convey the impact of the issue, but my audience doesn’t remember who Vendor X is or does, my message isn’t nearly as effective.

Theoretical Formula for the Mental Model

Actual RRR = Standard RRR / % audience engagement / % active unbiased listening / % familiarity with subject

  • Standard RRR: the general amount of repetitions required to retain one piece of information
  • % audience engagement: this is the percent of attention of your audience that you can reliably have at each repetition moment. If you are in a 1:1 conversation with someone who is fully paying attention to you, it’s 100%. If you are in a virtual meeting with dozens of people, I’d bank on ~50% engagement.
  • % active unbiased listening: this is the percent to which your audience is listening with an open mind, ready to receive new information. If the audience believes they already know the information you are sharing, they will be biased and hear what they expect to hear, even if that’s not what you were saying. This comes up often when plans are frequently changing; if a deadline has changed from the 15th of the month to the 10th then to the 12th, you audience might not hear you when you say it’s been changed to the 20th, because they believe they already know the latest information.
  • % familiarity with subject: this is the “warmth” factor I mentioned above, and it captures the percent to which the audience has a basis of understanding of the subject. For example, if I would like a software development team to remember that we intend to utilize AWS over Azure, not only do they understand the words I said, they understand the implications of that decision without too much further discussion. If you read that and don’t even know what those words mean, let alone why that decision is important, we need to take a deeper dive.
    • P.S. They are both cloud hosting providers. AWS is Amazon Web Services, owned by Amazon and Azure is owned by Microsoft. They don’t have a major impact to the end user of applications, but there is a major difference in the technical implementation between the two.

All of this is theoretical, of course. It would be next to impossible to define a true RRR for each piece of information, but you could get story point style with it of relative RRR. If an idea or piece of information is directly adjacent or just one layer deeper than an existing retained idea, then it will be lower. If it is a new piece of information, or complex, or there are multiple parts of it that are new, it is relatively higher on the RRR scale.

If we run a few scenarios with a Standard RRR of 10:

Talking to dev manager 1:1, new information, majority familiarity with subject:

10 / 100% / 100% / 80% = ~12.5 Repetitions needed

Talking to an accountant in a virtual meeting with 10 other people, new information, limited familiarity with subject:

10 / 50% / 100% / 20% = 100 Repetitions needed

How to apply this mental model

  • First: don’t get frustrated when you’ve told someone something once or twice (or way fewer times that it took you to understand it)
  • Second: You must be very particular about the information that you surface to others; if you only talk to an executive once a week, and you bring up something important (that has a 10-repetition retention rate) every other week, it’s going to take 20 weeks for that to sink in!
  • Third: Remember that things you know well are likely because you’ve had a lot of exposure to them. If you’re getting confused looks, take a quick step back to reassess your audience to see if you can guess how many times they’ve heard this before. If the number is low, take an extra minute to “reintroduce” the information to them.
  • Fourth: Whenever you get the opportunity, overexplain yourself. Be a broken record on concepts that you want people to retain. You’ll feel a little dumb for being so repetitive, but people will know more of what’s going on.


Agree? Disagree? Did I leave anything out? Let me know in the comments below.


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