Today I wanna show a list of the BEST market sizing case interview examples around the web.
I wanted this best-of list to be at least 5 or 6 items long, but that simply wasn’t possible.
I watched all of the videos available to write this. As it turns out, most of them are either misleading or just a waste of time.
This called for a change of plans.
The list I’m going to give you has…
If you just wanna get an idea of what market sizings are and just want to watch some video examples, you’re in the right place. Follow on.
But if you’re past that phase, you should be looking for content that will actually help you take your market sizing skills to the next level.
If you already know what market sizing case interviews are like and want to practice with harder examples that you could realistically find in a McKinsey, BCG or Bain interview, click here to skip to the second part of this article.
There you’ll find two harder examples with guidance on…
- how to use them,
- what you should be learning from them,
- and next steps to improve even further.
Let’s dive right in.
#1. US breakfast market sizing
Your client is a quick service restaurant that’s currently focused on their foot-long sandwich.
They’re considering entering the breakfast market, and they would like your help estimating the market size for breakfast in the US.
- 25% of americans eat breakfast daily.
- 30% of those eat at home.
- Of the 70% that eat out, 50% buy breakfast on their way to work and 20% bring it from home.
TAKE-AWAYS
- Cases from McKinsey, Bain and BCG first round will be harder than this.
- Notice how it’s easier to follow the candidate’s logic when they present their approach and structure before choosing asumptions or doing any kind of calculation.
- The candidate did a great job performing a reality check by the end of the estimation. That’s a habit you absolutely MUST develop before your first interviews.
#2. US cheese market sizing
TAKE-AWAYS
- The assumptions chosen by this candidate were overall shallow. A real interview might require more logic behind them (especially price of pound of cheese and ammount consumed per week).
- Segmenting the consumers into tiers is a great habit, and it’s common for candidates to overcomplicate when they do that (with several different assumptions for each segment). This candidate kept it simple, and you should follow his lead.
- Notice that in this example, the candidate is also asked to reality check their answer. Although many market sizing example videos don’t show this, reality checks are a crucial element in this kind of interview.
Part 2: two market sizing cases designed specifically for you
I was a bit annoyed by the fact that I could not find A SINGLE market sizing case interview example video anywhere on the internet that was on the harder side of the spectrum.
That’s a bit outrageous, given that 90% of you will find at least one market sizing case in your journey through consulting interviews.
That’s why I designed these two cases for part 2 of this article.
Part 2 will have two market sizing cases in slide format that’ll allow you to practice harder estimation cases by yourself and compare your answer to high-quality ones.
What you will NOT find here is the interaction between candidate and interviewer. My assumption is that you’ve already gotten that from the previous videos.
What you're gonna find...
...and how to use
You might not even need to ask any questions. That’s fine.
If there are any issues in there that you would have assumed but not explicitly communicated OR that didn’t even cross your mind, pay attention to that. It would have been a miss in a real case.
DO worry about your assumptions being strongly backed up by some kind of data and logic.
Find something to compare it that would tell you if you were orders of magnitude away from the right answer.
You wanna make sure that you’re not saying, for example, that 1/3 of the US population is made up by cab drivers, or that the shoe market represents 10% of the Chinese GDP.
By doing that, you’re showing your interviewer that you care about the quality of your numbers and that they won’t have to stay up at night reviewing your model if they ever manage you in a project.
Now it’s time to get to work.
#3. US online dating market sizing
TAKE-AWAYS
- The reality check on slide 5 caught the big mistake in the final answer. Two traits make this a great reality check: (a) it compares the final result to outside values; (b) the candidate states how much he would find feasible in comparison to the outside value.
- The second follow-up question is a common one in market sizings, even if your answer is correct. The interviewer wants to check if you can find to which variables the final result is more sensitive, and which assumptions are less trustworthy.
#4. Gun market in Italy
TAKE-AWAYS
- This case is a great example of when clarifying questions are great to tighten the scope of the estimation AND to show business sense. If the candidate tried estimated all of these markets, he’d likely get lost. If he had just ignored them, in the best case scenario he’d lose the chance to impress his interviewer. Worst case scenario, the interviewer would mark him down for forgetting that there are several other potentially relevant markets.
- The purchase of objects to replace old ones is a main driver in the gun market, as well as in many other durable goods markets.
- Since guns are replaced every 8 years (candidate’s assumption), the replacement rate should multiply the total existing guns from 8 years ago, not current total existing guns. The interviewer might have challenged the candidate on this part of the structure to see if he’d catch that mistake by himself.
- In some situations, the growth of total existing items might be more relevant to total sales than replacement of old ones. Think, for example, refrigerators, in a country where many people suddenly emerge from poverty, or where there’s a sudden increase in available credit.
What’s next?
You’ve seen what a case interview is like and you were even able to practice some of the harder ones.
That puts you in fair advantage, given that these cases are scarce to practice, but frequent in McKinsey, BCG and Bain interviews.
Now, I wanna help you pick your next step, with more free, high-quality content.
Just let me know which of these best fits your needs:
“I still don’t feel safe that I’d do well if I got a market sizing case in my interviews. I’d like a step-by-step approach to tackle them and in-depth practice material.”
mehrasa
Hello Bruno
first of all, thank you for these exercises. I have a Q regarding case #4.
I don’t understand why you assumed the growth rate of gun market 0%,
what I did is as follow and my result also is close to the figure, the interviewer told you as a following Q:
first I calculated the population over 18y.o who can carry guns legally –> 45 mil
then I assume 10% of them, can be licensed as a gun owner (as police men for instance) = 4.5 mil ppl
then I assumed the replacement rate every 8 years which would be 12.5% + the growth rate of 1% (the police academy graduates who can carry guns) –> 13.5%
4.5 mill * 13.5% = 600k
then multiply the price of the gun that you estimated 200 –> 120M
** if instead of eight years, we assume the replacement in ten years, we can reach the 100M of market size
for the reality check, i normally try to find that calculated number per capita and see whether makes sense or not (I donno if it is the right general approach for reality chk when it is applicable of course)
in this case 60 mil / 120 mil = 0.5$ per capita which makes sense for gun, I think
I am wondering whether my approach is right?
Julio Tarraf
Hey Mehrasa,
1- I assumed that the net change of the drivers doesn’t change much: population change close to zero. % above 18 not changcing much, % competent to carry a gun not changing much, % who actually get permit (so either motivation to get a permit or ease to get a permit) not changing much as well. And guns per person not changing much (change in how many people have over 1 gun, and on how many guns they own).
If you have a reason to say the police force is growing (more people coming in than going out), and you can justify that that would mean a 1% growth (rather than negligible), that’s fine.
2- Your structure is missing the # of guns per person who owns guns. Algebraically that has to be there, even if you want to argue that it’s close to 1. Otherwise your interviewer has to assume you didn’t think of this issue (and thus would miss it when it were relevant, like it could be if we were talking about cars or suits, for example).
3.1- It’s actually 120M Euro / 60M people, if you wanna get to euros per capita (money over people, instead of people over money).
3.2 – I find this number unusually hard to reality check. Your check is about as good as mine (which I think is not the best possible).
– Julio
mehrasa
Thank you Julio for your explanation
the point 3.1 is valid and thanks for pointing out to my mistake