"I couldn't believe these 'easy' market sizing questions cost me the offer at THREE top consulting firms"


Back in 2012, when I first applied to jobs in consulting, I made a frustrating, costly mistake...

I underestimated estimation and market sizing questions.

And then, they bit me in the ass.

Not once... Not twice... 

I failed estimations in THREE DIFFERENT FIRMS that year.

(Over four different cases... Two different McKinsey partners tested me on this.)

You can see it for yourself:

I don't know what's worse: to fuck up two estimations in the only final round that I got to go to (McKinsey) or to miss the opportunity to EVEN GO TO A FINAL ROUND at two other target firms because of a couple of (seemingly) straightforward market sizing cases...

Back then, I thought estimations were supposed to be easy. I didn't give them enough credit.

I had spent all my time working on my analyses (making sure I wouldn't make any math mistakes), and trying to guarantee I'd be able to structure any business and public sector cases that came my way... 

You know, doing those things that most candidates spend most of their time on.

And then, by the time I went to my actual interviews... 

I was overconfident and underprepared when it came to estimations

And you know what? 

I wish I could tell you it was just bad luck... That the interviewers had a bad day, or that I got an unusually difficult estimation...

But I can't. It wasn't bad luck.

I got my first warning sign when I was rejected at Kearney by a market sizing case... 

Then at BCG...

But I still ignored them when it was time to go to my McKinsey Final Rounds: 

"Partners will obviously test me with something tougher than mere estimation questions..."

That's what I thought, despite my experience in the first rounds at the other firms.

And then the McKinsey partners did exactly the opposite of what I was expecting.

I got TWO estimation questions in my McKinsey final rounds.

And they weren't your usual market sizing case... They were MUCH HARDER.

I hadn't even prepared enough for "regular" market sizing cases... 

Imagine what happened when I got these "partner-level estimations" that I had to solve in front of two McKinsey partners?

Of course, I blundered both of those interviews and threw my last chance away.

One of the partners told me in the feedback call: "We really liked you... But we don't think you're ready. I encourage you to try again next year..."

Yep, I'd have to wait a full YEAR before I could interview again.

This simple, silly mistake of underestimating estimations has cost me three offers.

The months of preparation, dozens of mock-interviews and several rounds of real interviews with interviewers who had (otherwise) liked me were now completely irrelevant.

All of that time and effort WASTED.

And this didn't just happen to me...

I wish I could say I'm an outlier.

I wish I could tell you that very few candidates have trouble with estimation questions, or that these indeed are the "easy type of questions" to most candidates.

But the truth is that candidates get rejected due to simple estimation questions ALL THE TIME:

B2B estimations are TOUGH. Now, think about it... This guy's WHOLE CAREER would've been different had he been proficient in solving this type of estimation case when he had that interview.

And it's not just TOUGH estimation cases that get candidates rejected... Take a look at this guy:

This solution isn't too bad on paper, but candidates often do slight mistakes on the way they justify their reasoning, communicate their approach and react to follow-up questions that put in check their credibility with their interviewers.

This of course, begs the question... 

Why does this happen?

Why do candidates get rejected in estimations and market sizing cases so often, in first and final rounds?

The reason is in plain sight...

No one teaches you how to answer estimation questions properly


You and I know that there's a ton of subpar preparation material out there...

But I can't think of a single topic that is taught in a more ATROCIOUS way than estimations and market sizing cases.


Take a look at this one paragraph from a popular book:


Why on earth would someone think this way of categorizing estimations would be useful to any candidate?

It's like categorizing healthy food items into Fruits, Vegetables and PREPOSTEROUSLY HEALTHY FOODS.

I could make fun of Mr. Cosentino all day, but I'd be missing the target... 

All the other resources I've ever seen have the same three fatal problems that will severely hamper your chances of getting the job if (when) you get an estimation question in your interviews...

FATAL PROBLEM #1: The examples they give are NOTHING like the real questions you'll get in real interviews

Imagine you were studying for a test. Let's say it's a math test...

One of the first things you'd look for are examples of questions (and answers) that resemble the ones you'll get in the exam. You'd look for questions similar in type and difficulty.

Well, guess what?

The questions you see floating around in books and websites are way less complex and much, much easier than the ones you'll find in real interviews -- especially at McKinsey, BCG, and Bain. 

(And firms like Kearney, Roland Berger, and Strategy& do often have some extra tricky estimation cases.)

For instance, here are the examples that a popular website mentions as representative of consulting estimation questions:

No wonder some candidates skip preparing for estimations properly... 
They think this kind of stuff is the real deal!!

Even Youtube doesn't do a much better job... 

Not long ago, Julio set off to watch every video on estimations and market sizing out there and curate the best ones for you in a new article in our website.

Here's the email he sent after his saga:


It's borderline IMPOSSIBLE to learn estimations properly if all you see are examples that are on the easy side.

It's like going to a math test thinking you'll get one-variable equations and getting differential calculus instead. 

You can study as much as you want, you'll still fail miserably.

But having examples that are way too easy is only the first fatal problem of current resources...

FATAL PROBLEM #2: Current resources give you examples of answers that WOULD NOT PASS REAL INTERVIEWS.

This one gets me REAL MAD.

For instance, take a look at this proposed answer to an estimation question in Case in Point:

Your interviewers would challenge these assumptions very strongly ("How do you know there are just 6 stations in your town?", "Why is your town representative of the whole US?", "What makes you so sure of the 5,000 figure?", "What about trucks and highways?") and you'd fail the interview if not able to address these concerns.

Even if we overlook the fact that this guy's suggesting you to make shit up because it divides by 30 (???), and try to look at the bright side, to the fact that his structure at least is mathematically right...

... Still, 80-90% of interviewers would reject a candidate had he "solved" this case like this.

To me, a good preparation resource is one that teaches you how to answer questions in a way that ACTUALLY GETS YOU OFFERS.

Anything less than that is subpar.

And it's not just Case in Point...

Coincidentally, I found on another popular website another answer example to the same "gas station" estimation (which goes a long way to show how much variety current resources are showing you...)

Here, take a look at it:

Now, this is definitely a much better way to estimate the # of gas stations in a given location.

But would it pass the interview?

Not necessarily.

And here's why: as important as having a logical tree and some assumptions hanging on top of it is...

... It's just as important how you'd defend your logic and assumptions to an interviewer.

Two different candidates could have completely different results (e.g. getting the offer vs. being dinged before the interview was even over) using the exact same tree and the exact same assumptions.

Why? Because they'd justify their structures and assumptions in different ways... Then one of them would reality check the answer well enough to make the interviewer comfortable and the other would not.

A good answer has things like:

  • The logic through which you'd defend the specific structure you're using to an interviewer (vs. an alternative approach).

  • Why the specific level of depth they're suggesting in the answer was chosen.

  • The reasoning behind EACH assumption (which this last example leaves you wondering, for example) -- this is SUPER important, and interviewers will grill you on this all the time in a real interview.

  • The specific segmentation pattern that would make the most sense to certain assumptions (and those that wouldn't make sense at all).

  • The reality checking comparison that would be used at the end to validate that the number you got to makes sense or not.

Having those things talked through in your answer (vs. simply a structure and some numbers) makes it complete. It puts the interviewer at ease that you're someone who'll be able to model scenarios in a reasonable way once you join their teams, and that you actually know what you're doing.

It's very hard to learn to solve estimations well from current resources without those kinds of nuances... Even worse when they give you answers that are plainly wrong. 

(Especially because, as a candidate, you can't always differentiate the good from the bad.)

But there's a third fatal problem that makes it almost impossible to learn estimations well enough to feel confident and competent in your interviews...

FATAL PROBLEM #3: There's no proven method that GUARANTEES you'll solve any estimation and market sizing case.

Suppose you're really driven to really learn to solve estimations at a high level of performance. 

You really want to get the offer, after all. 

Here's what you're handed as instructions...

"Base your assumptions on some sort of logic". 
Preposterous advice, straight from a famous book.

... Then I'm sorry to bring you the bad news, but you're pretty much SCREWED.

I'm not even saying some of this stuff is plainly wrong... I've already said that.

The main problem is that it is NOT EVEN PRACTICAL.

Pretty much all advice on how to solve market sizing cases out there boils down to the following: be logical and use reasonable assumptions.

Yeah -- duh.

I guess you could say that to race car drivers as well: "When racing, make logical decisions, based on reasonable assumptions."

Or to theoretical physicists: "When trying to disprove string theory, use logic and good assumptions."

The problem with that kind of advice is that, even though it sounds good, it doesn't actually help you when you have real struggles, such as:

  • Your interviewer just asked you 'what's the market size for professional cameras in your country' and you're there frozen, nervous as hell trying to come up with an approach that will work and not make your life harder...

  • Your interviewer doesn't like the one structure you came up with and now you have to come up with yet another one, as if the first wasn't hard enough already...

  • You're pressed to justify an assumption that, honestly, you just said a number without giving much thought to it... And now you're stuck in your head trying to find a reason why it makes sense but all the reasons feel like BS to you...

Unless you want to risk failing at three firms because of estimations as I did, you'll need something more reliable than that.

You'll need to know the patterns and systems that allow you to know exactly how to approach any estimation question an interviewer gives you instantly, no matter how weird or difficult they are...

You'll need proven techniques for structuring, segmenting and assumptions that consistently delight interviewers... And then, you'll need methods to reality-check your results with confidence so you can finish your interviews on a high note.

You'll also need preparation material that warns you about the common traps interviewers will put you in, and teaches you how to safely get out of those.

No current material on the market does that. They simply say "Hey, all you need is to be logical -- trust me, everything's gonna be okay".

So, nowadays we have resources that teach estimation questions and market sizing cases that:

  • Are way too easy and much simpler than the ones you're gonna get
  • Show you unreliable (and sometimes plainly wrong) answers to those questions 
  • Don't give you an actual method to solve these questions that you can rely on

No wonder so many candidates are caught unaware and get rejected with estimation cases.

Could it get any worse?

Unfortunately, yes...

Estimations are WAY MORE COMMON than you think


I used to think of estimation cases as an afterthought.

I thought they were mainly used by boutique companies or early at first rounds.

This was due to both ignorance and the impression that I got from the very same materials that didn't teach me how to solve them well. 

I had the perception (from these materials) that estimations weren't that important, and I guess some part of me thought that if my "trusted materials" weren't giving it enough importance, it must be because they didn't happen often in real interviews.

I spilled my water and slipped on it...

So, how common are estimations?

Julio and I have coached hundreds of candidates through thousands of interviews at different firms and offices, across all continents.

Here's what we've found:

  • You'll get an estimation question in about 40-50% of the first-round interviews you have, except at McKinsey. McKinsey very rarely has estimation questions in their first-round cases (though that could happen).

  • You'll get an estimation question in about 30-40% of final-round (partner) interviews, including at McKinsey.

And here are the nuances:

  • In first rounds at BCG and Bain, the estimations you get are likely to be 5-10 minute questions within broader cases (market entry, private equity, etc.). 

  • In other firms' first rounds, you're as likely to get an estimation question within a case, as you are to get a pure estimation case (i.e. the only case question you get in the whole interview is an estimation, usually market sizing). In a pure estimation scenario, there's very little room for error as they have no other way to evaluate you.

  • When partners do estimations (again, 30-40% chance), they're either the only question they ask or the main question they ask (and they'll ask other questions after you do the estimation). Partners also tend to have very challenging estimations that are often unusual.

Still don't think it's a big deal?

Well, if you consider that you have a 30% chance of getting an estimation in every interview, what do you think are the chances that you'll get at least one estimation in each firm you apply?




It turns out that if you have a 30% chance of getting an estimation per interview, and you have 6 interviews at a firm, you have a whopping 88% chance of getting at least one estimation before you get an offer at that firm.

Check the math out:

A 30% chance of getting an estimation is a 70% chance that you won't.
70%^6 gives you the probability you won't get an estimation in 6 interviews: 12%... 
... Which means there's an 88% chance you'll get one in at least one of those interviews

You can run your own assumptions, and the conclusion is pretty much always the same: 

You're almost sure to get at least one estimation question before you get an offer from a consulting firm.

(And often you'll get two or more of these questions, just like it happened to me in my McKinsey final round.)

And when you do get one of these questions, you better be pretty damn sure about what you're doing, because...

Estimations are HIGH STAKES -- they can get you rejected more easily than any other type of question


Make a math mistake in a normal Quantitative Analysis question, and you get a ton of opportunities to recover: these questions are always one small question within a much broader case...

Forget a key factor or two in a Framework or Brainstorming question and you're usually fine: if you had a bunch of other good key insights and just forgot one or two small things, your interviewer will usually forgive you for that...

Estimations are different. They're high stakes.

Unlike pure structuring questions (Frameworks, Brainstormings), if you forget one single variable, your whole structure is wrong -- the equation doesn't add up.

It doesn't really matter how many other insights you had. An equation without all variables is a wrong equation, and a wrong equation can cost you the offer.

The other thing that makes them high stakes is that, unlike pure analytical questions (Analyses, Charts), there's little room for recovery. 

Making a mistake in an Analysis, for example, can be pretty bad, but you have a couple things going for you... You're usually 10-15 minutes into the case, so you built credibility with your interviewer already. Also, you'll usually have other analytical questions in the case, so you can prove your mistake was an isolated incident.

Not with estimations.

In the scenario where the estimation you got is the only question of the case -- if it is the case itself -- you can't mess it up for obvious reasons. 

There won't be another question where you can make it up for your mistakes. The whole impression the interviewer will have of you will be dependent on that.

Now, not always the estimation will be the standalone question of the case...

But even when it is not, it is usually a KEY question. 

If you get an estimation within a market entry, product launch or private equity case, for instance, that is usually one of the most important questions of the case, and one that will take a good chunk of the time too.

In both of these situations, messing up the estimation is messing up the case.

And, in most firms, if you mess up the case, you've messed up the round. 

You might be invited for another interview, but most likely that will be, as it happened to me, a year from now.

But there is a third factor that raises the stakes for estimations: 

They're the one single type of question that can give your interviewer a well-rounded assessment of your consulting skills.

Specifically, that's why partners love estimation questions so much. 

Estimations are sort of a "mini-case".

They're much simpler than a full-fledged business case, but they test your structuring, business sense, analytical and communication skills altogether.

Estimations are a simple, but complete way for an interviewer trying to assess your fundamentals. Each part of the estimation process reveals key skills to the interviewer -- and they can always follow-up with more questions to learn more about how you think.

So, to sum up, estimation and market sizing questions are:

  • High stakes. And thus, highly likely to be a deciding factor in your offer should you get one in an interview...

  • Frequent. You're almost certain to get in any firm you apply to, even the top ones...

  • Largely ignored. Traditional materials don't give you realistic examples, reliable answers and a trustworthy method to solve them. And because of that, most candidates are underprepared.

No wonder so many otherwise well-prepared, intelligent candidates fail due to this type of question so much.

The good news: it doesn't have to be this way


Fast forward to the year after I was rejected. I decided to follow that partner's advice and apply again to all consulting firms I could.

So, what happened? Did I get estimations in my interviews this second time I applied?

Of course I did.

But this time, things were different.

I nailed every single estimation questions that I got. 

Not only that, there was no luck involved. I knew I'd nail each and every one of them as soon as the interviewer spoke the words -- before I even put pen to paper.

For instance, my last interview at Bain was with a senior partner. Not any senior partner, but the office manager. 

Yep, the top guy.

What did he choose to interview me with? 

You guessed it... An estimation case.

Here's the case question:

Estimate BMW's call center costs.

As soon as he spoke those words, I smiled. 

Even though it's not your usual estimation question, I knew I could effortlessly build a customized structure for it.

I did it, and presented a 3-layer structure to him.

He said:

"Good job, but I think we'll need to go deeper than that."

As soon I broke down each bucket of the structure, he'd ask me to go one layer further. 

Then again.

It ended up being a 50-minute estimation case. 

Whenever I structured a bucket, the partner would incessantly ask for a deeper and deeper structure. 

When it came time for choosing the assumptions, he didn't go light on me either -- he doubled down on questioning me and challenged every assumption as if he did that for a living (in a way, he did).

Can you imagine being nervous, in front of the most senior partner in the office, having to go deeper and deeper in your rationale in what seems like a never-ending quest for a more detailed MECE structure and better thought-out assumptions and not losing your nerves?

He'd ask things like:

  • "Have you considered that these call center reps will take vacations?"

  • "What about our employees that get pregnant? Doesn't that add to the cost?"

  • "Shouldn't the time delay before the rep picks up the phone affect your cost per minute?"

  • "How do you think the fact that BMW is a premium brand affects how often their customers actually call their call center? And how would you know how long these call are? Your personal experience isn't a good basis for these assumptions..."

I had never seen an estimation case go this way. 

He wanted so much detail into my structure that I ended up with TWO pieces of paper just to fit the structure.

I pulled it off and ended up with a 6-7 layer MECE structure and the most thought out assumptions of my life.

Julio and I included this Bain Final Round estimation as a drill in our estimations course, Master Market Sizing

As I finished the case, exhausted but proud of the work I did, he smiled broadly:

"Very good job, I think you're one of the best people I've ever seen at this"


At that moment I knew I'd get that offer.

But regardless of the offer, I just felt happy with myself. 

I was proud that I went from losing three offers because of estimations to really feeling confident at solving one of the toughest ones that were ever thrown at me.

I later talked to other candidates who were being interviewed by the same partner that day. They all said he used the same case and was as detail-oriented and picky with them as well.

Many were a bit bitter about the whole situation -- "I wish I had prepared for something like this, but how on earth would I know this was a possibility?"

I didn't talk to them again, but my guess from how they were feeling is that most of them got rejected that day.

I, unlike the other candidates, didn't feel bitter, nor anxious.

I solved the case, I didn't get stuck, I had strong answers to all his follow-up questions and the partner himself said he really liked me. 

And later that day, I got the offer.

What was different this time around?


The true difference between this time and the first time I applied to consulting and got multiple rejections was that in the meantime, I stopped behaving like a "candidate" and started behaving like a real consultant.

What made my interviewer like me so much was that, as I was solving the case, he felt like he was talking to a fellow Bainee, not just another candidate.

But how exactly did I achieve that?

Between the first and the second time I applied to consulting, one thing happened: I worked for 9 months in Venture Capital.

This would be completely irrelevant to this story if it weren't for two random facts:

1) In Venture Capital you have to estimate markets, revenues and even individual cost lines of a start-up all the time.

2) I worked directly with two former consultants.

Fast forward a few months, and while every other candidate was trying to impress that Bain partner "using logic and assumptions", as Case in Point and other resources suggest... I was solving that exactly as his own consultants did in the real project that inspired that case.

I had an unfair advantage...


All I had to do to solve that estimation and to answer any follow-up question that came my way was to do exactly what I did at the VC firm day in and day out.

What's more, because I directly worked with two former consultants, the methods I was using to estimate in the VC firm, as well as in that partner interview, were the exact same methods that the consultants that partner worked every day with used to estimate things for their own clients.

This gave me the ability to:

  • Instantly know 2-3 approaches to any estimation the interviewer threw at me, and which one was best in which situations...

  • "Read my interviewer's mind" whenever he asked a follow-up question to know exactly why he was asking that question (my former boss would ask me the exact same questions), and then give the perfect response to address exactly his concerns...

  • Know which methods would feel reasonable to my interviewer whenever choosing an assumption or reality checking a result -- and which ones would feel like complete BS (I had 9 months of experience being called out on the BS).

Now, the bad news is that it doesn't make sense for you to get a job in Venture Capital and spend 9 months learning this skillset like I did...

The good news is that you can learn the exact same skillset in just 1-2 weeks -- without having to switch jobs.

... and now you can have an unfair advantage too.


Last August, Julio and I were sitting at a coffee shop discussing much of what I'm telling you today.

We were talking about how poorly prepared most candidates are when it comes to estimation cases...

... And how that's expected, as the resources that they have to prepare for this type of question are lousy and misleading.

To put it nicely, we weren't happy with what was out there.

(I was outrageously annoyed, irritated, PISSED OFF that the bar for content quality was so low.) 

We were also talking about how many people were emailing us, asking for us to make more content on estimations and market sizing:

And then came the thought...

What if we took everything we know about estimations and market sizing and made a comprehensive course that helps candidates become outstanding in solving them?

We took out a notebook, ordered another coffee and started brainstorming ideas of what such a course should have.

Initially, we had HUNDREDS of ideas.

But as we dug deeper, we noticed that there were only 3 things candidates really needed:

Patterns, techniques and practice.

Here's why...

  • Patterns allow you to hear an estimation question from an interviewer and instantly know at least 2-3 proven approaches to solve it, even if it's a question you've never heard before. They take all the risk off the table, ensuring you can answer any question, no matter how easy, hard or obscure.

  • Techniques help candidates with specific weaknesses and challenges. Some candidates have a real hard time creating a mathematical structure, coming up with defensible assumptions, or even doing the math. Yet, you're always one technique away from turning a major weakness into an invaluable strength.

  • Practice helps you internalize the patterns and the techniques. Focused practice in a wide variety of estimation cases makes you feel confident and prepared to face any question. It gives you the experience you need to answer questions like a real consultant.

At the end of the day, we were over-caffeinated and eager to create that course.

We spent hundreds of hours cracking the code to estimations for you


Over the next few months, we rolled up our sleeves and designed our dream course on estimations.

We created a list of all estimation and market sizing questions we saw in real interviews.

These were cases that Julio and I got personally while interviewing at firms like McKinsey, BCG, Bain, Kearney, Roland Berger, Monitor Deloitte, etc. 

Then, we added cases that former coaching clients got at dozens of different firms and hundreds of different offices.

We wanted to make sure that the method we created was going to work for all of them. 

We also insisted that the examples we had in the course were realistic, not oversimplified questions like the ones you see in traditional materials.

We then created our system: a combination of patterns that made solving any estimation case easy.

This ended up becoming what we now call "The Estimation Blueprint". 

Think of it as an "algorithm" to notice the pattern behind the estimation question that is asked, and to solve it flawlessly.

Finally, we gathered our best, proven techniques that have helped real candidates overcome common challenges in the estimation process.

Techniques that: 

  • Could teach people who had trouble with structuring, how to structure any estimation with ease.

  • Gave "instant" creativity to non-creative candidates on how to come up with no-BS assumptions and reality checks.

  • Made math quick and error-free even to people who couldn't do math in their heads.

  • Allowed candidates to quickly come up with insightful answers to your interviewers' most common follow-up questions.

In the end, we had a system like no other...

This system will help you answer ANY estimation and market sizing question (even the most obscure ones)


After creating this system, we reality checked it against the list of market sizing problems we had from real interviews.

The result?

It was easy to use this system to solve every single one of them, flawlessly.

Yes, even the most obscure questions. Even those that 90% of candidates wouldn't even know how to start. Even those filled with trick questions and misleading information designed to derail all but the best candidates out there.

And the reason why this was possible is simple:

This system is nothing more than a collection of the patterns and techniques that real consultants use when estimating numbers.

Just like I learned to estimate markets, revenue and cost figures, and other numbers like consultants do when I was working in Venture Capital with former consultants... You can learn the same skillset (though much, much faster) by learning this system we put together.

And because the patterns and techniques are exactly the same that these consultants use, you'll be able to estimate the same numbers that they themselves can, using the same methods that they themselves use (though most are unconscious that this is what they're doing).

It's the shortest path to:

  • Effortlessly solve any estimation question that an interviewer throws at you.

  • Feel confident you can get yourself out of any situation, be it a tricky assumption that's hard to justify or a sneaky follow-up question that you've never heard of before.

  • And have your interviewer let out a sigh of relief as you start solving the case, as they see that they've finally found a candidate that "gets it" and knows what they're doing.

And today, you're one of the first to find out about it...

Introducing...The only practice-based program that teaches the blueprint, the patterns and the techniques to solve ANY estimation and market sizing question -- even those at the partner level!

Imagine if you could sit next to Julio and me for 20+ hours and learn everything that we know about Estimations and Market Sizing.

Imagine if you could learn all our systems and patterns that we've internalized over years of experience doing and teaching this... 

And if you could do a "mental download" of all the best techniques for structuring estimations, choosing assumptions, doing math and reality-checking results we've developed over these years... 

Techniques that have taken candidates who were at the "bottom 10%" of those skills and taken them to the "top 10%" in just a few days.

And then imagine if you could internalize these systems, patterns and techniques by going through 20 estimation drills with us. (Then having us tell you, for each one of them, the most common mistakes people make, and the important insights that are transferable to other estimations, too.)

This course is as close as it gets from being with us guiding you through every step.

How Master Market Sizing works

The course is divided into three parts, and was carefully built in a way that you'll be able to dramatically improve your estimation skills in the shortest amount of time possible.

First, you'll learn the most comprehensive system to tackle any estimation question ever created: The Estimation Blueprint.

Your goal is to start every estimation with a practical, insightful approach that has a MECE structure.

The problem is: how can you know you'll be able to do this regardless of what your interviewer asks you to estimate? 

I mean, they can ask you to estimate anything.

Without the proper systems, this is impossible

But in the first module of Master Market Sizing, you'll learn that not only that is possible, it's actually easy and obvious. You just need the right Blueprint in your head.

Then, get access to our "private vault" of In-Depth Techniques for a la carte methods, systems, techniques and insights into the major challenges candidates have.

Here you'll find things like: 

  • Our "Structuring Toolbox":  the exact techniques we used to teach unstructured candidates to turn them into "structure-generating machines" when it comes to estimations.

  • The "Assumption Playbook":  7 proven methods to "creatively" come up with reasonable assumptions that are credible to interviewers (even if you're not creative).

  • Our in-depth guides to excel in Clarifying questions, Calculations and Reality Checking.

  • Deep dives into the most common follow-up questions that interviewers ask (that derail most candidates) and how to answer each one effectively.

This is the material you need to go from "below average" to "top performer" in any specific aspect of estimation questions.

Finally, learn and internalize the patterns and techniques through our 20 practice drills of common, non-conventional and partner-level estimations.

If you want to be a top performer in estimations, a blueprint alone isn't enough... Even the techniques on top of it won't give you everything you need.

You also need experience.

The way you'll get this valuable experience within Master Market Sizing is by doing practice drills.

And we didn't simply "throw in" 20 random practice drills to enhance your estimation skills.

We were thoughtful. 

We've carefully selected the drills and situations that'd give you the most experience for your limited time.

We've blended "common types" of estimations along with "non-conventional" types and even "partner-only" estimation questions so you could learn from every single possibility out there.

And because of this careful curation, by doing these 20 drills, you'll expose yourself to a wide variety of estimation-related situations. 

This will give you more experience in estimation cases than some candidates who have gone through 50+ real estimation interviews have.

These three parts together will give you the patterns, techniques and practice that you need to dramatically improve your estimation skills in a short amount of time.

Here's what you'll learn as soon as you join Master Market Sizing:

Module 1: 

The Estimation Blueprint

By the end of this module, you will have a blueprint to identify patterns and solve ANY estimation case.

You will learn:

  • The 5 Common Types of Estimations:  the patterns and key variables behind the types of estimations that come up the most, so you can instantly identify and solve them with little effort and 100% certainty.

  • How to solve compound estimations such as B2B market sizing cases by "stacking" the 5 common types on top of each other. This skill will put you ahead of 99% of candidates by turning "impossible cases" into easy problems you can break down into the common patterns.

  • The 4 ways to size a market: the four approaches you can take to size any market that will help you go beyond the obvious, add variety to your arsenal and save your ass when your interviewer wants you to solve the case in a specific way (for example, because they have specific data to give you that wouldn't fit the "normal" structure).

  • How to add depth and insight to each of the 5 steps of the estimation process with our go-to techniques and scripts to clarifying the case, communicating the approach, structuring your estimations, choosing assumptions, doing the math and reality-checking your results.

  • Our exact scripts and recommendations for specific situations such as how and when to take notes using each of the three methods we recommend, when to ask for data vs. choosing your own assumptions, and how to know if your interviewer is looking for a simple 2-layer structure vs. a deep 5-layer structure.

Module 2: 

In-Depth Techniques

By the end of this module, you will have learned our best tools and techniques to instantly recover from your specific weaknesses (such as structuring, assumptions, math, reality checks) and turn these skills into valuable strengths.

You will learn:

  • How to ask clarifying questions and communicate your approach using two little-known techniques that are highly effective in getting your interviewer to trust you before you even structure the case (while all other candidates are rambling and unsure where to start).

  • The "Structuring Toolbox": Our 4 go-to techniques to break-down any estimation or bucket from scratch (including how to segment effectively and that show you how to break down "percentage buckets")

  • The "Assumption Playbook": 7 techniques to find and justify assumptions that work even with uncreative candidates. We'll also show you how to create your "fact bank" so you know the numbers that you do need to have memorized (and feel safe ignoring those you don't).

  • Our 5 favorite mental math techniques that allow you to develop bulletproof, fluent math in just a couple days -- including our "Crystal Ball technique" that is proven to take candidates with a 50% mistake rate to <1% mistake rate in their interview math. 

  • How to always have a reality-check up your sleeve through 3 versatile techniques you can use in every estimation and 2 advanced ones that are well-known to working consultants but barely seen among candidates.

  • The ULTIMATE reality-checking method that you can use in ~50% of your estimation cases and will immediately make your interviewer trust your results and skills.

  • How to deal with the 6 common types of follow-up questions so you have full control of your interview and earn your interviewer's nod of approval (in the same critical moment that other candidates are feeling anxious and confused).

  • The 7 specific insights that interviewers expect the greatest candidates to have when dealing with variables like "growth rate", "utilization rate", "supply capacity", etc. that will make you seem brilliant without you having to rely on a stroke of genius. These specific insights are especially useful in interviews with partners and other senior interviewers.

Module 3: 

Typical Estimation Drills

Your first 7 practice drills were carefully chosen to help you internalize the 5 most common types of estimations (that makeup ~80% of estimations in case interviews).

We'll tackle classics like: "How many gas stations are there in your city" and "Estimate the profits of your favorite burger restaurant".

We call these "classics" because we've seen dozens of interviewers from different offices (and even continents) using these exact cases (or very similar ones) with candidates.

Then, we'll move on to more difficult cases such as: "How many neurosurgeons are there in the world" and "Estimate the market for online SAT prep"

These drills, while tougher, still fit perfectly within the '5 Common Types of Estimations' that you'll learn in the "Estimation Blueprint" module. 

This will help you develop the pattern-recognition muscle to understand that certain "weird" cases are actually slight variations of estimations that you already know how to solve.

Module 4: 

Non-Conventional Estimation Drills

Here you'll learn from 8 drills of estimation cases that don't really fit the patterns you've learned.

We'll show you exactly how to adapt those patterns to specific situations or even how to create structures from scratch.

You'll learn from tricky situations that, although unique, have underlying concepts that are used over and over again by interviewers from multiple firms and offices.

Some examples of cases in this module:

  • "How many cows are there in the world?"
  • "What's the value of all residential real estate in a city?"
  • "How long would it take to move a 30-year old landfill of a city?"
  • "How many people go through Heathrow airport every day?"

The cases in this module will help you improvise effectively by adapting the most common patterns and techniques without breaking their underlying principles. 

This will enable you to solve any estimation question thrown at you with the confidence of a working consultant.

Module 5: 

Partner Estimation Drills

This module will get you trained to solve the hardest types of estimations, that you'll only see at final rounds in top firms.

You'll learn from 5 estimation cases embedded with unique situations, the toughest follow-up questions, and complex interview dynamics. 

This makes these cases less like "simple estimations", and more like business strategy discussions, assessments of an industry's trends or forecasting modeling exercises.

MBB Partners tend to love cases like these. 

They start off from a deceptively simple estimation case, and guide candidates through a complex, high-level discussion of an industry or situation. 

They're testing things like:

  • How far (and deep) your business sense can go.

  • Your ability to think of second-order effects and non-obvious implications of findings.

  • Your ability to turn "common sense" qualitative facts into quantitative forecasting models, and to translate the results of these models back into "common sense" recommendations to your clients

We've included 5 drills in Master Market Sizing that are specifically designed to prepare you for a host of partner-level situations like that.

And by the way...

No one else is preparing for this.

We haven't found any cases online that reflect this type of situation. 

We've also never met a single candidate that can do mock interviews at this level (which means they're relying on luck for their own interviews).

If you're shooting for an MBB offer, these Partner Estimation Drills will give you a significant advantage that no one else can get -- which might be the difference between multiple offers and multiple rejections.

"Is Master Market Sizing for me?"

Master Market Sizing isn't for everyone.

As with any of our other programs, we want to make sure you only join if this program is going to be valuable to you.

Another thing we want to make sure of is that if this program is for you, that you have no doubt about it and feel comfortable joining.

Master Market Sizing IS right for you if...

You have a weakness in estimations/market sizing questions. 

If you know from experience or direct feedback that your estimation skills are not there yet, you will get a ton of value from this course. 

It will reliably get take you from feeling helpless with estimations to being a top 1-2% performer in this type of question.

You're okay or even great at estimations, but want to take the risk out of your offer. 

In high-stakes interviews such as final rounds at a target firm, merely solving the case isn't enough -- you want to have an outstanding performance. 

It also helps with your confidence to be sure you'll be able to solve any estimation thrown at you. 

Master Market Sizing will help you both with being certain you can solve any estimation, as well as taking your skills to a top 1% level.

You want to learn estimations FAST. 

This is the only program that will improve your estimation skills reliably and consistently every single day. It is the most direct way to significantly improve your estimation skills.

While the program itself has 20+ hours of content, there are effective ways to get 80%+ of the benefits in as little as 3 days of learning and practicing. 

(Check out the FAQ section below to learn more about this.)

Master Market Sizing IS NOT right for you if...

You haven't yet finished the estimations module of Case Interview Fundamentals. 

Master Market Sizing is an advanced course on estimations and market sizing and it wouldn't make sense for you to join before you go through the essential, fundamental materials we provided in our free course. 

(In case you're planning on completing that soon, you could still join now.)

You didn't like our estimations module from Case Interview Fundamentals.

Even though this course goes much deeper and has many more (and more difficult) examples than the Estimations Module in Case Interview Fundamentals, the teaching style and format of the videos is similar. 

If you didn't enjoy our free course, you won't get value from this one either.

You just want to watch the videos and not do any practice. 

This course will not help you if you don't put in the practice.

If you passively watch the videos but don't do the drills out loud, we can't promise you to get the results you want.

You haven't yet learned the basics of solving business cases. 

For most people, this means having done at least 10-15 cases with other people and feeling comfortable solving a case from start to finish.

It doesn't make sense to go deep on estimations if you can't reliably solve a case yet. If this is you, wait and join later.

You can't comfortably structure full cases yet (such as profitability cases, business strategy and etc.). 

If this is you, I recommend you master the structuring Building Blocks first, either using our free content in Case Interview Fundamentals or by going deeper by using our Structuring Drills program.

Then, once you've mastered that, come back and join Master Market Sizing!

PS: There is ONE exception for the last two situations: if you know with 100% certainty that you'll get an estimation case (e.g. because HR said so). 

In this case it makes sense to join and go deep into estimation cases even if you can't structure and solve other case types yet.


Frequently Asked Questions

How do I know that this course actually works?

This course is composed of a variety of systems and techniques that we used to teach candidates back when we did 1-on-1 coaching.

This means that every single technique and method taught in Master Market Sizing was tested in two dimensions:

  • They're effective to help real candidates with real struggles (and not just "supposed to work" but not really learnable in practice).

  • They're effective in real interviews (because we'd get almost real-time feedback from our clients going into real interviews with a variety of consulting firms).

This is what makes our students say things like this:

If you're, for some reason, unsure about the effectiveness of this course, you can try it risk-free as per our guarantee below.

What if I don’t have enough time to go through the full course?

I'm gonna be honest with you. That is not what you should be asking yourself. 

The question you should be asking yourself is, “do I need to improve my estimation and market sizing skills right now?”

Because if you need it, working on it is the single most leveraged use of your time.

But if you really don’t have that much time, we’ve built the course to accommodate that.

One of the first videos in the course is a guide to help you decide which videos to watch and which to skip depending on your situation.

For example, if you don't have issues with assumptions, calculations and reality checking, you can safely skip the videos on those topics.

In fact, if you have a very specific issue with estimations (structuring/assumptions/reality checks), you'll get 80% of the benefit of this course from only a handful of videos. And this is GREAT.

You can watch those first, maximize your chances of passing your interviews a week from now and then have the whole course available so you can hone your skills before the next rounds or before your interviews with another firm.

In fact, several of our students have used this course successfully when strapped for time.

How is this course different from the Estimations section of Case Interview Fundamentals?

Master Market Sizing goes much deeper, showing you the patterns to solve ANY estimation question, techniques to excel in each step of the estimation process and the street smarts to respond faster and better than other candidates in common traps and situations.

It also gives you 10X more practice at a much deeper, and (often) more difficult level. 

We'll give you not only basic estimation cases that are expected from all candidates, but also unusual and even "partner-level" estimations so you're prepared for pretty much anything.

Does this course only work for consulting firms?

This course is targeted for candidates aiming for top consulting firms, such as McKinsey, BCG, and Bain.

It also works perfectly for other consulting firms like Roland Berger, Strategy&, Kearney, Big 4 consulting firms, boutique firms, etc. 

Finally, it does work with non-consulting firms that ask estimation questions in their job interviews (such as start-ups, banking and large corporations). 

The methods used are exactly the same, and many times the interviewers asking these questions are ex-consultants themselves.

Will this course actually make me a top performer in estimations and market sizing questions?

The vast majority of candidates under prepare for estimation questions due to ignorance or lack of a coherent prep strategy.

The good news: it becomes easier to differentiate yourself if you have the right methods and invest a bit of time and effort to practice.

Estimating well isn't that hard -- all you need is to know what the interviewer is testing when they ask a question of this type, and what should you do to show them you've got that type of skill.

Master Market Sizing gives you the best methods available everywhere to estimate easily and effectively in case interviews (and even in real life).

It also gives you the practice you need to actually learn those skills and methods.

All that's to say that -- if you put in your effort, follow the method and don't give up easily if you find anything difficult -- you'll be in the top 5% of candidates when it comes to solving estimation cases in as little as a week. Many who take this course will be in the top 1% with the same time and effort.

Try Master Market Sizing for 30 days, 100% risk-free!

We've worked hard to make sure this is BY FAR the best program on estimations and market sizing available anywhere

We've tested every system, every technique inside the course with real candidates (many of whom instantly eliminated their weaknesses with this type of question). 

We know it works, and we know it will help you master estimation questions.

And we want you to see it by yourself - which is why we offer you to try the whole course risk-free for 30 days.

If after 30 days you don't LOVE this course, we want you to have 100% of your money back.

Just send us an e-mail, show us you did the work and we will return you 100% of the investment of the course. We'll even eat the credit card fees.

This guarantee lasts for 30 days, which is more than enough to go through the whole course.

You can learn the Estimation Blueprint, learn every technique inside the course, and practice 20 different, high-quality estimation drills that will help you solve any estimation and market sizing question - all 100% risk-free.

Join Master Market Sizing NOW, and you'll get access to:

  • The Estimation Blueprint: our bulletproof system to flawlessly solve any estimation and market sizing case -- each and every time.

  • Complete methods to know how to solve the 5 most common types of estimation cases before you even put pen to paper.

  • The 4 ways to size any market -- your set of options to have more variety and flexibility when sizing any market (so you're not stuck when your interviewer wants you to use a different approach).

  • Our best practices, scripts and specific recommendations to be in full control of the estimation case in each of the 5-steps to solve it and beyond (for example, when interviewers ask you specific follow-up questions or put you into ambiguous situations).

  • Our "Private Vault" of in-depth techniques to turn weaknesses into strengths when it comes to clarifying the question, structuring your estimation, choosing assumptions, doing math or reality checking your results.

  • The 7 common "specific insights" senior interviewers expect top-notch candidates to have when solving estimation cases that they use to separate merely good candidates from those who'll get offered the job.

  • 20 high-quality drills of "typical", "non-conventional" and "partner-level" estimation questions so that you can get practical experience in solving realistic estimations on your own time (and then compare your answers to our in-depth answers and explanations to get even more insight into the estimation process.

Get instant access to Master Market Sizing now for just $197

You'll get 12-months of access to the whole material and will be able to start learning and practicing right now

Join Master Market Sizing Now!

Beware: Hidden risks don't hide forever

Here's are 4 emails I received recently:

"I missed an opportunity at Roland Berger"

"I was rejected at a final round for an Estimation/Market-sizing question"

"I was recently rejected from Bain. My final round included TWO estimation cases"

"I was rejected in my Strategy& Summer Internship due to market sizing errors"

I usually love getting emails from candidates, but getting these in my inbox HURT me bad.


Because I know how they felt when they were rejected because of estimation cases: a mix of "no one told me this could happen" and "I could've prepared for this, if only I knew..."

And because I know how impotent you might feel when you are in front of the interviewer, get the estimation question that's between you and your offer and then think to yourself: 

"Oh crap, I don't even know how to start this one..."

If you're interviewing with a consulting firm, you have a "hidden risk" between you and your offer.

You risk getting an estimation case, without knowing how difficult or sneaky they can be.

The problem with hidden risks?

They don't hide forever.

I got two first-round rejections and one McKinsey final-round rejection back when I first applied.

Candidates like the ones who emailed me faced the same.

You're in luck, though. You've read this far, so to you, the risk isn't hidden anymore. 

Today you've learned exactly why estimation questions are so dangerous, why using traditional resources isn't a reliable way to face them and what to do instead.

You're left with a few options...

One option you have is to keep working with traditional materials...

Yes, they have unrealistically easy examples...

Yes, they have simplistic answers that are hard to trust and rely on...

And yes, they lack any methodology besides telling you to "be logical and reasonable".

But I get it... They're openly available and everyone uses them, which makes them feel safe.

The problem is: most people who use them also don't get any offers. 

Doesn't sound like a good deal to me.

A second option... Hiring a coach.

This is actually a very good option!

Unfortunately, it's a bit risky and very expensive.

Risky because most coaches out there are not good and don't care about you. 

They'll sell "mock-interview services" by the dozen, give you a standard case, and then some generic feedback in the end. Some of them don't even care whether you get the offer or not.

If you do find a good coach that cares and that knows how to teach estimations (most don't focus on this), it's going to be very expensive to learn this skillset from them.

I'm talking about thousands of dollars.

There's a third option -- the one I don't want you to take: to ignore the problem.

Sadly, this is the option most people take, though.


Because "it's what everyone's doing".

Because "it's not gonna happen to me".

Because "I'll solve this problem later".

This is the worst option, because if you DO get a market sizing question, you're screwed. It will cost you the offer. Then, you'll regret it and wish you took the time to prepare for it.

The final option: join Master Market Sizing today.

Julio and I have worked very hard to make sure it is by far the best option for people who want to really excel in their estimations.

We also didn't want you to take risks, so we made the program risk-free for you.

This means that you can learn everything we have to teach regarding estimations and market sizing (which, being very honest, is a lot), practice with our drills and then decide if the program was worth it for you or get your investment back.


But at the end of the day, whatever choice you make, just promise us one thing:

Do something about your estimation skills.

You’ll regret it if you don't a few weeks from now.

You’ll wish you did something about it.

And you might have to wait another YEAR to interview at your dream consulting firm again.

It’s just not worth taking that risk.

If you never want to risk an offer because of a market sizing or an estimation case ever again, give Master Market Sizing a shot. We know you’ll love it as much as we do.


Join Master Market Sizing today and get instant access to:

  • The Estimation Blueprint: Our systems and patterns to tackle any estimation and market sizing case, no matter how tough or weird.

  • Our "private vault" of in-depth techniques: that will turn your weaknesses into strengths and take your skills in structuring, assumptions, math, and reality-checking to a whole new level.

  • 20 curated estimations drills: from the common types that you're likely to get, to weird, obscure questions that you'd only get at the partner level -- our 20 drills will prepare you to face any situation as if you had done it before.

Master Market Sizing is the only program you need to tackle ANY estimation and market sizing question like a real consultant would.

Get instant access to Master Market Sizing now for just $197

You'll get 12-months of access to the whole material and will be able to start learning and practicing right now

Join Master Market Sizing Now!