## Guide to the McKinsey PST 2020 Update

*(Hint: Bookmark This Page - It's Long)*

The McKinsey Problem Solving Test (also known as the McKinsey PST) is a math computation, data interpretation and logical thinking test used by McKinsey to determine which candidates are granted a first round case interview. In general, candidates whose resumes McKinsey deems acceptable are invited to take the test. Based on feedback from hundreds of test takers, you must pass the test in order to get the interview. **There are few to no exceptions to this rule.**

**Why the McKinsey PST Exists**

The reason McKinsey uses the test is because there are a certain set of numerical computation and logical thinking skills required to be successful in consulting. While standardized math tests like the quantitative sections of the SAT, GRE, or GMAT do test math computational skills, it is possible to get perfect scores on these math tests but fail on the job in consulting.

It's my interpretation that McKinsey developed the McKinsey Test in order to test those skills that regular math tests do not adequately evaluate. In particular, these skills involve data interpretation and critical numerical reasoning.

Now when I hear the words "data interpretation" and "critical numerical reasoning", it always reminds me of those college entrance exam tests that were challenging, seemingly arbitrary and pretty much not useful in the real world. But, it turns out these skills actually have a very practical purpose while working as a consultant.

These skills allow you to:

1) Read a graphical chart (or the data spreadsheet that was used to create the chart)

2) Grasp what the "data is conclusively telling you" and separate from what the "data is suggesting (but not definitively so)"

3) Write a 1 - 2 sentence "headline" at the top of a Powerpoint slide state a logically correct conclusion

In other words, you end up using these skills every single day as a consultant. And if you use these skills incorrectly, then either your manager or partner has to redo your work for you (which means at some point you will get fired) or the client notices the logical flaws in your work and it makes your firm, your partner and your manager look bad (and of course means that at some point you're going to get fired).

Now you would think looking at a chart and writing a powerpoint headline is not a very difficult skill. I mean anyone can look at a chart and write a headline, but you would be surprised by how many people actually get the headline wrong. In other words, a LOT of aspiring consultants and even some first year consultants see that data and come to the WRONG conclusion.

From a McKinsey partner's point of view, it's a complete disaster if someone on your team lacks this skill... or even worse THINKS he has the skill, but actually doesn't.

It is such a big deal that McKinsey has gone to extensive effort to create this test and have thousands of candidates around the world take this problem solving test. All of this effort is taken for the sole goal of hiring new consultants who can do 1) do math accurately, 2) do it quickly, and (most importantly) interpret data CORRECTLY.

In short, being able to solve problems logically is a BIG DEAL.

**McKinsey PST Format**

The computer-based test consists of approximately 26 questions and lasts 60 minutes. No business background is needed to take the test, but being familiar with a few commonly used business terms is useful (see the McKinsey PST Frequently Used Terms section of Part II of this Guide Below). You are permitted to use pen, pencil or paper. No calculators or computing devices are permitted.

Typically a graphical chart or table of numerical data is presented along with some descriptive text about a company or industry. 4 - 5 questions follow that refer to the chart. The two most problem question types are:

**1) Math Word Problem - Given the data in Table X, calculate A, B or C.**

A, B or C might be profit margins. It might be figuring out which company's profits were larger two years ago. It might be calculating the difference in sales from today vs 2 years ago for two different companies - and figuring out which company had the bigger change.

In the US, we call these "word problems". The purpose of these problems is to give you raw data and information conveyed in a text paragraph, and see if you can figure out the math equation needed to solve the problem. Often the actual math computation isn't difficult (its just addition, subtraction, multiplication or division; often math problems are based on percentages - growth rate, cost expressed as a percentage of sales, or profits as a percentage of sales, sales of this year vs 3 years ago expressed as a percentage).

What makes the word problem difficult is a) Time, b) Time, c) Time.

Amongst those who pass the McKinsey Problem Solving Test, the consistent feedback was they finished with barely enough time. The most common reasons for making a mistake for a math word problem is misreading, misunderstanding, or misinterpreting the data presented or what the question was asking. The other big reason is computational error.

When I took my first McKinsey PST practice test, I actually missed several problems. To be fair, I had a newborn baby in the house and was sleeping 3 hours a night at the time, and I made a LOT of careless errors. My mistakes: I *thought* they were asking one thing, when they were really asking another. I rushed the computation, and made mistakes.

**2) Data Interpretation - "Given X chart, which of the following conclusions are accurate:"**

The other type of question isn't computationally intensive, but rather tests your logic and critical reasoning skills. You will be asked to refer to a chart or data table (mini spreadsheet with numbers) and asked some variation of the question: Which conclusion is correct?

Variations of this question including presenting you with potential answers that are a) definitively correct, b) could be correct but you can't be 100% sure, c) definitely wrong. The answers that are trickiest are ones that seem consistent with the data, but is NOT completely conclusive. In other words, you need to be able to look at the data and tell the difference between a factual conclusion vs. a hypothesis suggested (but NOT 100% proven) by the data

Skim the questions FIRST to get a feel for what you will be asked, THEN read the data table or chart. This allows you to get some idea of what you should be paying attention to while you look at the data or read the text.

- Read the text descriptions and the questions VERY CAREFULLY.
- Take the questions literally. (I made the mistake of assuming some of the questions were commonly used business analysis and jumped ahead to calculate what I assumed they were asking. What I should have done was look at what they were LITERALLY asking and just answer what they asked.)
- If your math computation skills are rusty, practice your math accuracy and speed. You do not have a lot of time to double check your computations on every problem. Some people don't have time to double check their computations at all. The more you're absolutely certain your math skills are accurate and quick, the more time you'll have to actually answer all the questions. (Once again, the main enemy of the test is time)
- For data interpretation / drawing a conclusion type questions, be careful of the multiple choice answer options that seems consistent with the data, but are not 100% conclusively supported by the data. The easiest way to do this is to immediately eliminate the answer options that are clearly wrong. Then BE CAREFUL in looking at the remaining options.
- For data interpretation question, one thing to ask yourself is "Is this conclusion correct under ALL scenarios?" - Just because the conclusion is true under the most common scenario doesn't mean it is true under all scenarios. For example, if you think B is the right answer because it is the conclusion you think is supported by the data, you should ask yourself "Are there any scenarios I can think of where conclusion B is not correct?"
- Remember a conclusion that is true MOST of the time is NOT the same as a conclusion that is true ALL of the time.
- Bring a watch to time yourself - do not assume every testing room has a clock.

**McKinsey Problem Solving Test - 3 Ways to Prepare**

The biggest challenge for developing your problem solving skills is there aren't many McKinsey PST practice test that are at a difficult level equal to that of the actual McKinsey Problem Solving Test. For a full list of practice tests available online, fill out the McKinsey Practice Test List - Request Form below.

There are three approaches you can take to prepare for PST:

1) Practice Computations

2) Practice Data Interpretation

3) Take McKinsey PST Practice Tests

Below are tips and resources for each of the practice methods.

**Practice Method #1: Practice Computations**

The first method is to practice the speed and accuracy of your arithmetic. The McK PST is a TIMED test. This is not the kind of math test designed to test the entire population of people with a wide range of math skills. It is intended to identify only those who are very good at math, logical thinking, etc... If you are really good at math, you will finish the test BARELY.

So even if you have a PhD in Physics or Math (I'm being serious on this), it is VERY IMPORTANT you practice your math computations. I get many, many emails from engineers who had 4.0 GPAs in school who did not pass the PST. Your math computation skills are a muscle. The more you use it, the stronger it gets. Keep in mind even if you calculate an integral effortlessly, it doesn't mean you can't make an error doing basic computations.

One resource I'd recommend to develop your computation accuracy and speed is www.CaseInterviewMath.com. This is a math practice tool that I developed for practicing: 1) arithmetic for speed and accuracy (both VERY important on the McKinsey PST) and 2) estimation math with large numbers (useful for solving some of the McKinsey PST word problems faster where precise math isn't necessary to answer the question, just an estimate will suffice.)

This tool compares your math accuracy and speed to other CaseInterview.com members and to my own test results as benchmark. This will help give you an idea of how your math skills compare with others; and whether or not you need to improve your math speed and accuracy to be competitive, or if you current skills are sufficient.

In addition to practicing math computations, you want to practice and develop your data interpretation skills.

**Practice Method #2: Practice Data Interpretation**

For data interpretation, the practice questions that most closely resemble PST questions are practice test questions from certain sections of the GRE. In particular, I would recommend practice "word problems" and "data interpretation" type GRE questions.

Keep in mind the actual McKinsey Problem Solving Test questions are harder and more sophisticated than the word problems and data interpretation questions in GRE. Sometimes the questions are combined -- word problem + data interpretation. Other times instead of presenting a straight forward problem, as you would see on the GRE, you'll see a more elaborate scenario (or multi paragraph story with one or more charts) where you have to figure out what information is irrelevant to the specific question at hand.

Remember, each chart is referenced by 4 - 5 questions. So for any ONE question, most of the information presented is NOT relevant to THAT particular question.

But before you work your way up the elaborate questions, polishing your foundational skills in word problems and data interpretation is a good idea.

*Data Interpretation & Word Problem Practice Resources:*

__Kaplan GRE Exam Math Workbook – Chapter’s on Arithmetic Review (if you're really rusty on math), Word Problem Practice and Data Interpretation Practice____Nova's GRE Math Prep Course – Sections on Percent’s, Graphs, Word Problems and If you're really rusty on math: Averages, Ratio & Proportions__- Cliff Notes Math Review for Standardized Tests - Word Problems Review
- Online Practice Resources:

Because GRE problems are much easier than the PST problems, you need to balance the nearly unlimited practice questions (that are too easy) available for the GRE vs. the much smaller pool of practice problems for the PST. In addition, there are only a few PST practice tests available online for free. The other practice tests available (including the ones I offer) do have a fee.

Additional Note: As of June 5, 2012, the GMAT is being revised to include a section on "Integrated Reasoning". From my assessment, this section of the GMAT has many similarities to the McK PST. If anyone has any experience with this version of the GMAT or as the test prep guides are updated to reflect this new section of the GMAT, please post your experiences below and I will incorporate the feedback into a revision of this guide.

**Practice Method #3: Take McKinsey PST Practice Tests**

The following are links to a few McKinsey PST Practice Tests.

*Links to Free Problem Solving Test Samples:*

- McKinsey Problem Solving Test - Sample Test Question on Data Sufficiency (from this website)
- McKinsey Problem Solving Test - Example Test Question on Data Sufficiency - Answer Guide (from this website)
- McKinsey Problem Solving Test 1 (from McKinsey Website)
- McKinsey Problem Solving Test 2 (from McKinsey Website)
- McKinsey Problem Solving Test 3 (from McKinsey Website)
- McKinsey Problem Solving Test Coaching Guide (from McKinsey Website)

Note: The consensus feedback from reader Field Reports is the actual McKinsey Test has a lot more reading than the samples posted above. My takeaway from this is that its important to read the questions FIRST, then read the text and charts. Keep in mind you are not reading a magazine article or a business school case. Your only mission is to answer the questions asked and to move on... QUICKLY.

With that in mind, I recommend reading with a PURPOSE in mind, as opposed to just for general knowledge. In other words, KNOW what you're looking for BEFORE you read. Then read carefully while hunting for the data you KNOW you will need to answer the questions.

Definitive Guide to the McKinsey Problem Solving Test |

@agnes

I just took the test at their German office last Friday. So very recently!

1.) Market shares I did not have to calculate, but many percentages and break-even type of questions related to some strange-looking graphs/tables I had no idea how to interpret. I feel like they were a lot more difficult than the practice tests. (Remember myself sitting by myself in this large conference room and laughing at myself for not being able to solve most of them).

2.) Something involving a luxury boat manufacturer (here the questions revolved around whether or not they could draw conclusions from the automotive industry in growing their revenue by leasing/financing options), an institution similar to Teach for America, and the third one I honestly do not remember, as I had such a hard time going through the test quickly.

3.) Reading the text in my opinion can make a difference, especially when the wording of the multiple choice are very similar. However, reading the entire case still did make me perform well on the test.

4.) I had the same issue with the time. I skipped so many questions and guessed more than half the questions (no kidding).

Strangely enough, although the test went horrible in my opinion, I just received a call (while typing this message) that I was invited for the second round. Don’t know about the test though and if this was considered in advancing me to second round.

And FYI, the practice tests online as well as GMAT and GRE did not help me in preparing for the test, as the majority of questions I feel are business judgment questions. In order to solve the numerical questions you need to understand the graph/table and the last part is being able to calculate quickly.

Best of luck to everyone!

So after having my PST, I will also share my experience;

There were 8 of us, and we were all placed in a tiny room, so do not expect any perfect working environment, people are all around you flipping pages and doing all kinds of noises and I guess that’s a part of the whole process. Other than that, we had three cases, although different to the ones mentioned so far, and much more text than in Kosher Franks. In fact I doubt anyone managed to read everything, it was in my opinion impossible. Anyway, I made it through and now I have my interviews. Good luck to the rest.

Thanks a lot for your comments! Good luck in your final interviews!

@polybutene: First of all, thanks a lot for a comprehensive answer.

I have my PST tomorrow, and at this point I have solved the practice tests and the 20-20 test. I haven’t done exceptionally well, but then again I see the logic once I see the answer and most commonly apply it afterwards in similar examples.

As I don’t really know anyone who has taken the test recently I can’t ask about any strategy in terms of choosing any specific case. Do you have a suggestion? Or any tip on what finance/mathematics area I should take a particular look at?

How is your process going now? Have you had your first interviews?

Cheers.

@Lukas: if it is of any help, I started with the last case and then I did the first one. In my test the second case was by far the most difficult. You don’t need finance at all, really, at all. You only need to work on percentages but you probably already know..my next step is the final round of interviews, I am currently preparing for that. I tried to help since I think the best for us and the best for McK is to have the best people and it is stupid to be rejected for a reason like you prepared on the wrong things. I would suggest after dinner don’t look at those sample tests again, watch a movie and go to bed early, just go there as relaxed as possible and good luck :)

@polybutene; Is there anything you recommend taking a special look at? (apart from the previous tests etc.)

@Lukas: Of course I don’t have answers but this is what I did and what I would suggest to do:

– Prepare in group, challenge each others. Who the fastest in math? I noticed I improved much in fast calculations. I am an engineer so not that bad with numbers but if you cannot improve math I think you can still improve confidence. I would say that arriving as confident as possible to the test helps being relaxed.

– Ask to the ones who took the test recently. I think the test is the same for several months (not sure). If you can ask someone who took it which one is the simplest case (there are three of them in the test) you should start with the easy one. Starting with the easy one helps you being relaxed since you notice the numbers coming out from your calculations to be among the possible answers. It means it is right and gives you confidence for the next questions. I had one of the cases on leasing. Since I was not confident with that I decided to skip to the next one and came back later. I think it helped.

– Do look at similar tests (not McK ones) but don’t get scared if you score poorly. As I said, I was doing quite good on the McK samples but not good on the others. Keep in mind that they can help you but they are not good indicators of the final result.

For what it matters, and I know because I hated when people told me before the test, try to be as relaxed as possible. Bring a mechanical watch since nothing else will be allowed, practise with the same watch. I have been able to finish all the questions since I skipped one when I noticed I spent 3 minutes on that. When you practise, try to copy the answers as if you were actually doing the test: you don’t imagine hoooooow much time it takes to be sure you are coping the answers in the right spot, allow you 10 minutes and then if you finish early you can go back to the questions you left unsolved.

If you have anything more specific, I’ll try to answer.

@Agnes: post your questions here, they might be useful to someone else if I know the answers :)

@polybutene: My questions:

1. Does the test involve a lot of tables of size 5 X 6 and above and we have to calculate market shares, percentages, efficiencies etc. for each option … I have no idea how anyone can calculate or estimate these within less then three minutes. Any tips in such situations?

2. What are some the recent cases that people have got on the test? Just to feel a bit familiar when on the hot seat.

3. What are people’s feelings in general these days about having to read the whole writeup before answering the questions? Has anyone really felt the need? The samples on McK website, most of the times, can be solved using just the question without really having to look much into the page-long writeup. Anyone shares this thought with me?

4. I get too much bogged down by time and end up not being able to perform at all, though I am good with my calculations and can solve them once the time is up (but that is of no use, you guys would agree). Any tips to help me out please ?

Warm regards,

polybutene, Hi, could you please send me your email address. Had some questions about the test. Rgds,

I took my PST today and passed (they let me know about 10 minutes after the end of the test). A guy told me he saw my score being 17/26, don’t know if that was the truth. In the sample test (kosher frank+2), I scored 20/26 on my first shot. The real test is neither easier nor more difficult than the sample one, imho. Maybe Fiji Cola is easier.

P.S.: For the ones who are taking Cheap Air/PetraEnergy/2020-test, my scores were 3/9-6/9-3/5. I think the McK one is not easier, it just better prepared compared to those ones. In the McK the right answer is just logical, in those ones may not be in my opinion.

Good luck to everyone, I hope to be a colleague of yours in McK in the future.

@polybutene: Hi, could you please send me your email address. Had some questions about the test. Rgds,

Hi polybutene,

Could you tell me where you did you find other practice test like Cheap Air and PetraEnergy. I found only 2020test

How long you spent in preparation?.

thank u

cheers

Did anyone solve the “PetraEnergy” PST?

I’m having the bigest trouble with their last question, particularly calculating the new profit margin after VAT is exempted…

Can anyone please walk me through it? I must be overlooking something, the problem is driving me crazy… not to mention undermining the tiniest bit of confidence I built up.

@hannah: Hi Hannah, Pass me the PetraEnergy PST, I will have a look for you.

please send the petraenergy PST to me ill really appreciate

@hannah can you please send me the PetraEnergy PST too. Thanks!

@hannah please pass me the Petra energy @ [email protected]

Hi Hannah, I see its been a while, but Ive been wondering if you could share the tip on the Petra question No9? Im also wondering about how they calculated the profit margin. Thank you.

Just heard back from the Lagos office?

Didn’t pass the test.

How soon can one retake it?

There is 1.5-2 years period before you can reapply.

Can we please have a lil chat?, am scheduled for the test in 2 weeks. need to know what to expect. thanks.

Hi Mo,

I have my PST scheduled for next week. I have done quite a bit of studying, however I only have access to about 4 sample PSTs. Do you have any useful tips for me? On how the actual PST compares with the samples made accessible to us?

Ayoyinka,

If you are referring to the McKinsey provide PST samples, the difficulty level of the actual test is similar. The main advice I’d give is to work smoothly, and not panic if you feel rushed for time. Most people who pass are sure they did not because they were pressed for time. The difficult level of the test is such that most people could pass if given enough time, so the time pressure is part of the test. One of the keys is to look at the question they are actually asking and before just making computations because you can, take a few seconds to ask yourself what is the MINIMAL level of computation needed to answer the question. This saves a LOT of time. Part of what they are testing is if you can determine when you need to do all of the computations to answer a question, and when you do not.

Also, I do have additional practice test samples available for an additional fee that I obtained from a 3rd party. These additional practice tests, including my videos of me actually taking a sample test while you watch and I explain what I am doing and why, are generally considered harder than the actual PST.

https://www.caseinterview.com/mckinsey-pst

Good luck!

-Victor

Hi Ayoyinka,

I also have my test this week, any luck with getting other practice questions, where are you based, perhaps we could share some information and agree to meet before our test.

Hi Tosin,

I have my test this week..what type of cases are being given these days? Women’s fashion, boat leasing etc? Please share your recent experience.

Hi,

Kindly share your experience. My test is in 3weeks.