The 100-Hour Rule: Forgotten Study Shows How You Can Become World-Class In 100 Hours

Michael Simmons
Accelerated Intelligence
12 min readJan 6, 2022


The year is 1976. Anders Ericsson is an unknown, newly minted PhD.

Little does he know that he is on the verge of what would be “the most surprising two years” of his career. Ericsson and his collaborator Bill Chase are about to begin the study that will ultimately lead to the 10,000-Hour Rule.

Though, what makes their seminal study most interesting is not what came from it (10,000-Hour Rule), but what should have come from it and didn’t…

Inside The Forgotten Finding From The Study That Spawned The 10,000-Hour Rule

The study design was simple.

Ericsson and Chase wanted to replicate a forgotten 1929 paper where two undergrads increased their ability to memorize random digits when shown them at a rate of one per second. Over four months, one student went from memorizing 9 digits to 13 and the other went from 11 to 15. This was a big jump.

So, Ericsson and Chase had two questions about the results that they wanted to address in their study:

  • “​​Was this sort of improvement replicable?”
  • “And, if so, how was it possible?”

On the first day of the replication experiment, undergrad Steve Faloon, like most people, was only able to remember 7–9 digits. Ericsson describes the amazing thing that happened next in his book

“From this point on, Steve slowly but steadily improved his ability to remember strings of digits. By the sixtieth session he was able to consistently remember twenty digits — far more than Bill and I had imagined he ever could. After a little more than one hundred sessions, he was up to forty, which was more than anyone, even professional mnemonists, had ever achieved, and still he kept going. He worked with me for more than two hundred training sessions, and by the end he had reached 82 digits — 82.”

To recap, a random undergrad became the best random digit memorizer in the world and broke past what he and the researchers thought was possible. He did this after only 100 sessions and without any expert coaching or the intention to be the best in history.

How is this even possible? Why didn’t Steve plateau at 11–15 digits as expected?

Ericsson attributes it to purposeful practice (later known as deliberate practice). Faloon did actually plateau several times, but he persisted and found ways to break through…

He could have just kept doing what he was doing and maxing out at eight or nine digits, session after session. But he didn’t, because he was participating in an experiment in which he was constantly being challenged to remember just one more digit than the last time, and because he was naturally the sort of guy who liked this sort of challenge, Steve pushed himself to get better. The approach that he took, which we will call “purposeful practice,” turned out to be incredibly successful for him. It isn’t always so successful, as we shall see, but it is more effective than the usual just-enough method — and it is a step toward deliberate practice, which is our ultimate goal.

In the following decades, Ericsson published 100+ studies on deliberate practice. In 2008, Malcolm Gladwell popularized this research with his book, Outliers. In 2016, Ericsson summarized his decades of research in his book, Peak. Tragically, Ericsson died in 2020 (incidentally, a few weeks after he participated in two group calls I had organized between top academic researchers in the space).

But the story need not stop there.

Ericsson and Chase pulled on one string, deliberate practice, and followed it for decades. But this is only half the story. They left another equally important string unpulled…

The Missing Variable In The Skill Equation

What is equally important but almost completely overlooked is the fact that someone could become the best at a skill in just 100 sessions — approximately 100 hours. This would seem to challenge the fundamental idea behind the 10,000-Hour Rule — the pattern that it often takes 10,000 hours of deliberate practice to become world-class at something.

Put differently, the skill acquisition formula we’ve culturally come to accept is the following:

Deliberate Practice * 10,000 Hours = World-Class Skill

But, what this formula misses is that time doesn’t have to be fixed at 10,000 hours. The reality is that the time required to become great varies. The more people spending more time learning a skill, the longer it will typically take to become world-class. The fewer people, the easier it will be to become.

This brings us back to Steve Faloon. Yes, deliberate practice was an important part of the equation, but so was skill selection. Very few people go about trying to become world-class at memorizing random digits. Therefore, Faloon was able to make history in just 100 sessions. If he had been trying to master tennis from scratch with deliberate practice, he wouldn’t have even come close to being one of the best.

With this new variable of skill selection, the revised skill acquisition formula looks like this:

Deliberate Practice * Skill Selection * 100 Hours = World-Class Skill

Now, let’s be real for a second. Memorizing digits is a gimmick skill that doesn’t pay the bills. While it’s rare, it’s not valuable.

What we really want to know is this…

Are there any truly valuable skills we could become world-class at in just 100 hours?

If the answer is yes, we’d expect to see elite learners using this approach and getting amazing results with it. And interestingly enough, we do. So let’s explore the question by understanding the learning formula of one of the best meta-learners in the world…

How Tim Ferriss Masterfully Selects Micro-Skills To Learn

Tim Ferriss has spent his entire career dissecting the learning patterns of top performers and proving them out in his life. Everything from his TV show to his books are about getting amazing results fast.

In his book, 4-Hour Chef, Ferriss details his method for meta-learning, which he calls DSSS:

Now, notice the first three rows. They are all about the value of skill selection. In Ferriss’ words:

“Material beats method” — Tim Ferriss

Ferriss is not alone (more on this later). But for now, with the DSSS method and Ericsson’s groundbreaking study, we’ve established the foundation for the 100-Hour Rule…

Enter The 100-Hour Rule

The 100-Hour Rule is the theory that to master a topic and get the benefits of greatness doesn’t need to take 10,000 hours. Rather, it can often take approximately 100 hours if you break down skills into rare and valuable micro-skills.

People who are great at the 100-Hour Rule (like Tim Ferriss) are able to find micro-skills that fall in the green quadrant better than others…

Why the 100-Hour Rule is powerful

First, the 100-Hour rule gives fast results.

When we focus on 100-hour chunks rather than 10,000-hour chunks we immediately get the benefits of mastery rather than having to toil away in obscurity for years. In other words, focusing on micro-skills allows us to get the benefits of greatness within dozens of hours rather than thousands. Put in yet another way, when we choose a big pond to fish in, we get drowned out by those with more experience. When we fish in rare & valuable small ponds, we gain the benefits of greatness fast.

Fast success is critical because most professionals who are juggling work, family, and hobbies don’t persist with skills when there aren’t big tangible benefits showing up. Not only that, there’s no escaping the fact that sucking at something isn’t as fun as being great at something, and it’s hard to persist at something we don’t enjoy:

“Many things aren’t fun until you’re good at them . Every skill has what I call a frustration barrier, a period of time in which you’re horribly unskilled and you’re painfully aware of that fact.” — Josh Kaufman

Second, the benefits of learning grow exponentially as we go from novice to competent to world-class.

When we learn more, we get more benefits:

  • Build a better reputation
  • Get better opportunities (jobs, projects, customers)
  • Can charge a premium
  • Make better decisions

And the fact that these benefits grow exponentially is key. As the world becomes more digitized, it becomes more winner-take-most. This winner-take-most dynamic occurs because when people pick who they hire, purchase from, or work with, they can pick anyone in the world and will always want to work with the best, which means the demand for the best increases. As a result, the rewards of being world-class can be 100x the rewards of just being competent.

Once you’ve gotten the benefits of learning one micro-skill, you can stack more on top and make even more rare and valuable skill combinations.

This stacking approach is typified by the world’s top entrepreneurs and investors…

Peter Thiel And Warren Buffet Follow The 100-Hour Rule

Identifying rare & valuable micro-skills to learn is similar to how top entrepreneurs identify micro-niches when they start new companies.

For example, PayPal co-founder and billionaire investor Peter Thiel advises entrepreneurs to follow the three-step process below:

  1. Start small in an area where you have a comparative advantage
  2. Dominate that niche
  3. Then scale to other niches

In Thiel’s book, Zero To One, he dives deeper into how finding a micro-niche is a key to avoiding competition and getting a foothold:

The perfect target market for a startup is a small group of particular people concentrated together and served by few or no competitors. Any big market is a bad choice, and a big market already served by competing companies is even worse. This is why it’s always a red flag when entrepreneurs talk about getting 1% of a $100 billion market. In practice, a large market will either lack a good starting point or it will be open to competition, so it’s hard to ever reach that 1%. And even if you do succeed: cutthroat competition means your profits will be zero.

Later in the book, Thiel makes the case that once you’ve dominated a niche, you can then find new niches:

Sequencing markets correctly is underrated, and it takes discipline to expand gradually. The most successful companies make the core progression — to first dominate a specific niche and then scale to adjacent markets — a part of their founding narrative.

To explain his thesis, Thiel offers Amazon, which started off selling books, and eBay, which started off with Beanie Babies (my highlights on Thiel’s book where he shares case studies).

Ferriss and Thiel are not alone in leveraging the principles behind the 100-Hour Rule:

  • Interestingly, Thiel’s three-step approach echoes Warren Buffett’s #1 mental model, which is the Circle Of Competence. This framework advocates the idea that you should always stay in niches where you have a comparative advantage. Focusing on staying in zones where you can be great is exactly what makes the 100-Hour Rule so powerful.
  • Jack Butcher built a $1m+ business in two years by first starting out mastering the rare & valuable micro-skill of creating quote visuals. Because the micro-skill was rare & valuable, he was able to become widely known within 100 hours.
  • I went from no audience to tens of thousands of readers in months by shrinking the scope of each article I wrote, going deep on the research, and aiming to write the best article on that topic in the world. Over time, I’ve consistently found that I can research and write one of the best articles in the world on any topic adjacent to something I know within 100 hours.

Tim Ferriss, Peter Thiel, Warren Buffett, Jack Butcher, and my story provide the beginning of a playbook for applying the 100-Hour Rule.

Now, it’s your turn…

How You Can Use The 100-Hour Rule To Make $1,000 Per Hour

At the heart of the 100-Hour Rule is the following 3-step process:

Step #1: Break skills into their subskills (i.e. micro-skills)

Keep chopping it up until the micro-skills are 100 hours.

For example, when it came to writing I broke it down into four components. Then, I broke those down one more level…

Step #2: Identify the $1,000/hour skills with little competition

Not all micro-skills are created equal. Some are dramatically more valuable. It’s critical to find what those skills are, because the best ones can be 1000x more valuable. In other words, some skills will only get minimum wage in the market. Other skills are worth $1,000/hour.

To find these $1,000 skills, plot the micro-skills you identified in step #1 on the following graph. To find a valuable skill, think about how much employers or customers would theoretically pay per hour for that skill. To find a rare skill, target smaller, underserved micro-niche like Peter Thiel recommends. Focus on the rare and valuable skills in the upper right quadrant.

Visual inspired by Rad Reads

In my own writing career, I started with mastering the micro-skill of academic research. I found that there was a treasure trove of insights that few people outside of academia even knew about. Amazingly, for every article I wrote, there was often dozens of researchers across disciplines who had spent their whole career researching the topic. Even though lots of people know how to do academic research in academia, I found that few outside of academia know how to.

Step #3: Learn $1,000/hour skills with a month-long learning challenge

The reality is that turning an intention from this article into 100 hours of deliberate practice is hard. Most people aren’t going to do it because the status quo of not doing anything is way easier. Plus, it’s hard to know on your own if you actually picked the highest value skill… or simply a mediocre-value one.

To help you go all-in and master a high-value skill, I created something for you. From November 28th to December 22nd, I’m doing a month-long learning challenge called Month To Master.

I’ve done dozens of learning challenges in my life, and each time I walk away with a new, valuable skill that I’ve learned. Here’s why challenges work so well:

  • Group support
  • Friendly competition
  • Accountability

If you like the idea of doing a one-month learning challenge and want to get a free preview of what it looks like, I’m giving away the first week of the challenge (November 28th to December 4th) to help you take the first step to rapidly master $1,000/hour skills in one month.

This is an immersive one-week experience that gets you taking massive action, and it includes co-learning calls with other ambitious learners.

If you want to make 2022 your breakthrough year (vs. regretting end-of-year that you didn’t take enough action), I invite you to join me now:

Start learning $1,000/hour skills — join the free challenge >>

This article was written with love and care using the blockbuster mntal model.

If there’s a link to an Amazon book, it’s an affiliate link, which means I get a small amount of compensation when you buy the book. This compensation does not influence the specific books I recommend, as I only recommend books that I read and love.

Part way through writing the article, I saw that others had used the 100-Hour Rule, but to mean to different things. To see those posts, check out Jay Shetty (2018) and Leo Polovets (2015).



Michael Simmons
Accelerated Intelligence

I teach people to learn HOW to learn / Serial entrepreneur / Bestselling author / Contributor: Time, Fortune, and Harvard Business Review