McKinsey PST: step-by-step guide

At IGotAnOffer, we have helped thousands of candidates prepare for their McKinsey Problem Solving Test (McKinsey PST). Students who go through our full training programme are a happy bunch: more than 80% of them are successful and end up getting an interview with McKinsey.

Preparing for the PST test can feel daunting, but it does not have to be. Over the past few years, we have developed a simple step-by-step system to get you from "What is the McKinsey PST?" to "I am confident I can crack the test". We have summarised some of the key things we have learned in this free guide.

Part 1: Why does McKinsey use a test? 

In your daily life as a consultant you will use your maths and logic skills more intensely than in most other jobs. McKinsey therefore wants to make sure you've got those skills before inviting you for their first round of interviews.

Skills tested by the McKinsey Problem Solving Test (McKinsey PST)

 

More specifically, junior consultants spend a lot of time on the following three tasks:

  1. Extracting data from graphs, tables and text. This data usually is in client documents (e.g. PDFs, Excel spreadsheets, etc.).
  2. Transforming data through maths computations and interpretations. This part of the job usually happens in Excel.
  3. Summarising their findings. This usually happens in Power Point and more rarely Word.

Not surprisingly, the McKinsey PST tests these three skills. First, you will be given graphs, tables and text documents and will need to quickly find the data in them. Second, you will need to either interpret that data or make calculations to select the right answer in the test. And third, you will also sometimes have to select the answer that best summarises the situation.

If you do well at the test, it is therefore an indication that you will do well on the job. All McKinsey PST cases are inspired from past McKinsey projects. The firm's intention is therefore reproduce the conditions of a project as much as possible.

Finally, the problem solving test is also interesting for McKinsey because it's an OBJECTIVE measure of your abilities. EVERYONE gets the same test. It therefore really enables the firm to compare candidates apple to apple. This contrasts with case interviews where interviewer ratings are by nature more SUBJECTIVE. And where it's therefore harder to directly compare candidates.

Now that you know why McKinsey uses the PST, let's turn our attention to the basic features of the test that you need to know about.

Part 2: McKinsey PST basics

The McKinsey Problem Solving Test is among the most difficult standardised tests you will likely take in your lifetime. It is therefore worthwhile spending time understanding the basics of the test to maximise your chances of success. Here are the 5 most important things you need to know about regarding the test.

McKinsey problem solving test basic characteristics

2.1 26 questions, 60 minutes

The McKinsey PST includes 26 questions distributed over three different business cases. Each business case refers to a company or organisation that is facing a challenge and that has hired you to help them find a solution. Challenges can go from profitability issues to decisions about whether or not to enter a new market.

Everyone would probably succeed at the McKinsey PST if they were given an unlimited amount of time to answer each question. What makes the Problem Solving Test such a difficult challenge is that you only have 60 minutes to answer 26 questions. That’s about 2 minutes per question and managing your time efficiently is therefore key to succeeding.

In certain offices, non-native English speakers are given an extra 10 to 15 minutes to take the test. You should get in touch with your McKinsey HR representative if you are in this situation and do not know whether you are allowed this extra time or not.

2.2 No business knowledge required

The PST test is designed to assess your numerical computation and logic skills. It is NOT designed to test either your memory skills or your business knowledge as outlined in McKinsey’s coaching guide. 

McKinsey does not test your business knowledge per say with its Problem Solving Test. However, being familiar with some basic business terms will help you feel more confident and allow you to understand certain questions quicker than other candidates.

We have put together the video below to help you master these essential business terms. This video assumes you start from 0 business knowledge and covers the basics incuding revenues, costs, profits and some ratios such as profit margin, growth rates, etc. If you are already comfortable with these concepts (e.g. studied business at university) you should feel free to skip this video.

2.3 33% of successful candidates

Every year, 200,000 people apply for McKinsey, but only 2,200 of them get a job offer according to the firm’s managing director. That’s a ~1% success rate. Based on that information, and on the different stages of the McKinsey recruiting process, we estimate that about 65,000 candidates get invited to take the PST test and that 33% of them succeed at the test every year.

If you would like to learn more about this you can read this article where we look at the different steps of the McKinsey recruiting process.

2.4 70% cut-off score

McKinsey does not communicate the exact cut-off score for its Problem Solving Test. At IGotAnOffer, our best estimate is that the cut-off is about 70%. This is based on our experience of successfully passing the test, as well as on conversations with hundreds of successful candidates over the past few years.

In either case, people who passed the test consistently scored above 70% during the last stages of their preparation AND performed well on the day. This means that on a 26-question test, you need to get at least 19 questions right in order to succeed.

There are a couple of things worth knowing about this cut-off score.

First, whether or not you succeed at the test only depends on YOUR score. It does NOT depend on how well other people have done at the test. If all the candidates in your PST session score higher than the cut-off score, all of you will progress to the next round of interviews. The outcome of the test therefore fully depends on you, which is a great incentive to do your absolute best at the test. 

Secondly, scoring VERY high at the PST can actually be a great strategy to be hired by McKinsey. A lot of candidates think that scoring about 70% will be just enough to get them to the next round of case interviews. However, your PST score will be used in later rounds of the recruiting process to decide if you will be made an offer or not. If in the final round you did as well as another candidate but only one position is available, McKinsey will likely choose you over the other candidate if you scored much higher a the PST. Scoring 90%+ can therefore be a great way to set yourself apart and our experience shows it is feasible with sufficient preparation.

Finally, we are often asked how much time one should dedicate to preparing for the test. In our experience, most successful candidates spend about 30h or more training. There are actually fewer candidates capable of passing the test without training seriously than most people imagine. The vast majority of candidates who end up working at McKinsey are bright but also very determined and motivated people who invested time and effort getting into the firm.

2.5 No calculator, no scrap paper

As a consultant, you will regularly have to make mental maths estimates in client meetings and discussions. This is the main reason why you will not be allowed to use a calculator during the test. You might have thought that nowadays consultants would use their phones to make estimates in meetings, but they do not tend to. In our experience this is to avoid disrupting the flow of the meeting and also a little bit to try to impress the client!

In addition, scrap paper will also not be allowed during the test. You will therefore have to carry out all calculations on the white spaces in your PST booklet. McKinsey likely forbids scrap paper for very practical reasons. It enables them to make sure no one has a chance to write down PST questions on scrap paper to bring them back home and distribute them to future candidates.

We therefore encourage you to take the PST tests in real conditions: no calculator, no scrap paper and in 60 minutes. In our experience, training in these conditions will make sure you perform to your best on the day of the actual test.

Part 3: McKinsey PST question types 

Now that you know everything about the test basics, let's turn our attention to the type of questions you will come across in the McKinsey problem solving test. They can be grouped into three categories. 

  1. Maths word problems: ~40% of questions
  2. Logic - Data interpretation: ~30% of questions
  3. Logic - Reading comprehension: ~30% of questions

Let's analyse each type of question one by one.

McKinsey problem solving test (McKinsey PST) question types

3.1 Maths word problems: ~40% of questions

In maths word problems, you will be presented with information in the form of graphs, tables and text. To answer the question, you will need to develop a maths formula and run computations based on that formula. Here is a typical maths word problem from McKinsey PST A, question 7:

To the nearest tenth of a percentage point, what is the difference between Germany's and Spain's average annual business sector growth due to productivity over the last 12 years?

A. 0.1 percentage points

B. 0.5 percentage points

C. 0.9 percentage points

D. 1.3 percentage points


To answer this question, you first need to work out the formula to calculate the annual business sector growth due to productivity over the last 12 years. And you then need to calculate these rates for Germany and Spain and compare the two.

In most cases the maths involved in these type of questions are not extremely complicated. It's mainly additions, subtractions, divisions, multiplications and growth rate calculations. The challenge is to do these calculations quickly and accurately. Remember, you only have about 2 minutes per question, so it's not uncommon to rush and to make a calculation error.

Another common mistake is to misunderstand the question, or to misread the data provided. In this example for instance, we are interested in the growth rate DUE TO PRODUCTIVITY. This is key as there are different drivers behind the overall growth rate. Missing that part of the question would lead to an incorrect answer.

In the tips and preparation plan sections of this guide we will discuss what you can do to overcome these challenges.

If you want to try your hand at Maths word problems you can try to answer this McKinsey PST question in under 30 seconds. Describe your approach in the comment section and take a look at how other candidates have answered the question.

3.2 Logic - Data interpretation: ~30% of questions

The McKinsey PST also includes questions where you are asked to assess different statements using data provided in documents. These questions are close to data interpretation questions in tests like the GRE or the GMAT. Here is an example from McKinsey PST A, Question 12:

Which of the following CANNOT be concluded from the information presented in Exhibit 3 regarding the sample of customers analysed?

A. Purchasing by customers in their first 90 days is an indicator of their value to Marcadia in their first year

B. Quintile 1 are the customers with the lowest profit margin for Marcadia

C. The average customer makes between 2 and 3 transactions in the first 90 days since signing up

D. The average one year customer value is $7.90


You will still need to use maths to answer these questions, but they are typically much less computation intensive than maths word problems. Instead they require you to use logic and critical reasoning skills which is why we call them logic questions.

One common challenge for these questions is to quickly find information on slightly different topics. For instance, some of the statements above are about Quintile 1 while others are about the average customer. This means you will have to look at the data in different ways to assess each of the different statements.

Amongst the different statements it will often be easy to eliminate one or two which will be obviously wrong. But the statements you will be left with will often all look like they COULD BE RIGHT. The challenge will be to find the one statement that's PROVEN BY THE DATA.

This is a mistake some of us made at IGotAnOffer the first time we took the PST. We sometimes selected statements that looked or felt right even though there was no data in the document to support them. This was a BIG MISTAKE. In the PST, an answer is only correct if it is PROVEN by the data available. If a statement is not proven by the data, then it cannot be correct.

3.3 Logic - Reading comprehension: ~30% of questions

Finally, the McKinsey PST also includes reading comprehension questions which will test your ability to draw conclusion based on a text extract. Again, these questions are somewhat similar to reading comprehension questions in the GRE. Here is an example from McKinsey PST A, Question 20:

Given the aim of the President of WFGLA, which would be the LEAST relevant question for the team to answer?

A. How can WFGLA get better at targeting people who are likely to donate?

B. How can WFGLA engage with people in ways that are more likely to result in donations?

C. How can WFGLA contact and communicate with their donors in a lower cost way?

D. How can WFGLA improve the execution of campaigns by the campaign cabinet?


This type of question is similar to data interpretation questions. But they involve no maths at all. They purely test your ability to grasp a situation based on a text document and to interpret which statement provided is most likely to be correct.

Again here, some statement will LOOK like they are true, but they won't be supported by the TEXT. And it is a common mistake to select those statements. Instead, you should focus on selecting the statement that's 100% LOGICALLY supported by the text.

Now that you know what type of questions you will come across, let's start turning our attention to how you should approach answering them.

Part 4: Tips for passing 

We've listed our top tips below to help you become a PST pro. Most of these tips come from our own experience of succeeding at the PST. We are also listing a few from McKinsey's PST coaching guide which we think you will find helpful.

Top 10 tips for passing the McKinsey PST

Tip #1: Answer ALL questions

You should answer ALL questions in the PST test because there are no penalties for wrong answers. Indeed, every right answer gives you +1 point and every wrong answer 0 point. As a consequence, if you hesitate between two answers or are running out of time during the test you should select an answer at random. With a bit of luck, this will help to boost your score.

Tip #2: Fill in the answer sheet as you progress (!)

We also recommend that throughout the test you regularly write down your answers in the answer sheet that you will be provided with. This may sound obvious but some past candidates who trained with us forgot to do that when taking the official test because of the stress!

They had to fill in the answer sheet in a rush during the last one or two minutes of the hour and came close to failing the test as a result. We encourage you to save yourself this last minute moment of panic and fill in the answer sheet as you progress :)

Tip #3: Skip questions if necessary

You will have 2 minutes on average to answer each question. At IGotAnOffer, the first time we took the test one of the mistakes some of us made was to refuse to skip questions. This was a BIG MISTAKE. It's very tempting to continue wanting to answer a question once you have already invested 2 minutes in trying to find the answer.

But in our experience, SKIPPING questions after 3 minutes if you are not making enough progress is actually the right strategy as it maximises your score overall. When you do this, you should obviously NOT leave the question unanswered. You should pick one of the two or three options you are hesitating between. This hopefully won't be a completely random guess as you will have probably eliminated some of the answers after 2 or 3 minutes.

Tip #4: Brush up your maths

We've helped thousands of candidates succeed at the test. And if they had one thing in common it's probably this: they ALL invested some time at the beginning of their preparation to brush up their maths. The maths calculations in the PST are not complicated; you will only need to do basic additions, subtractions, divisions and multiplications. The real CHALLENGE is that you have to do A LOT of calculations VERY QUICKLY and you won't have time to double check them. This requires practice.

Tip #5: Estimate

When you brush up your maths skills you should make sure to practice ESTIMATING results as opposed to doing precise maths. In a lot of cases, answers will be far apart enough for you to approximate results. You should definitely try this as it's one of the simplest things that can make you MUCH FASTER at answering questions in the PST test.

Tip #6: Plan THEN solve

A common mistake is to start doing calculations as soon as you are done reading the question. This is very tempting because you want to answer the question as fast as possible. However, doing this can actually be counter productive if you don't know EXACTLY what you are calculating. So our advice is to FIRST PLAN what you are going to calculate and THEN do the computations you need to do. This is the approach that's the fastest overall in our experience.

Tip #7: Looks correct ≠ Proven by the data

When you answer a PST question, it is usually fairly easy to eliminate one or two of the possible answers. The difficult part is to pick the right one amongst the two or three that are left. This is difficult because some of the answers you will be left with will LOOK CORRECT. But there won't be enough evidence in the documents proving that they are correct. The rule in the PST is that if an answer is NOT PROVEN BY THE DATA then it is not correct.

Tip #8: Start with the question

A question candidates often ask us when they start preparing is "Should I read the documents first and then the questions? Or should I read the questions and then the documents?" Everyone has got their personal preference. But the VAST majority of people we worked with found it more effective to read the question FIRST and to only then look for the information they need to answer the question in the documents. 

Tip #9: Speed read the documents

Time is very precious when answering PST questions. Once you have read the question and you know what information you are looking for you should SPEED READ the text. What we really mean by speed reading is that you should be SCANNING the text for the information you are interested in as opposed to reading line by line. Once you found what you needed you can answer the question and move on to the next one.

Tip #10: Charts and tables are often the key

Finally, we would encourage you to ALWAYS start with charts and tables when you are looking for information to answer a PST question. Charts and tables are almost always helpful to answer questions. But large sections of the text in the documents are sometimes irrelevant.

Now that you are up to speed with these McKinsey PST tips let's turn our attention to how you should structure you preparation to succeed at the test.

Part 5: Preparation plan 

What's the best way to prepare for McKinsey Problem Solving Test? And how do you make sure you succeed? In our experience the following 4-step approach makes for a great preparation.

McKinsey PST preparation plan

  • First, get familiar with the test and question types
  • Second, develop confident maths skills
  • Third, master a fast and consistent answering method
  • Fourth, practice on sample BCG Potential Tests

For full disclosure, this is the approach we teach in our McKinsey PST Training Programme, and more than 80% of candidates who have used it so far ended up being successful at the test. This compares with the estimated average 33% success rate for other candidates. But even if you don't end up using this programme, we would still encourage you to use this four-step approach. Trust us, it really works!

5.1 Get familiar with the test and question types

The first thing you should do if you have not already done so is take a few McKinsey PST tests to get familiar with the format of the test and the question types. 

Here are some PST samples you can get started with:

If you find any other interesting resources, please post them in the Q&A section below and we will add them to this list.

5.2 Develop confident maths skills

It is common to have rusty maths skills when starting to prepare for the PST test. This certainly was our case amongst the IGotAnOffer team when we first started preparing. And this is also the case of most candidates who we work with today.

However, in our experience, successful applicants tend to dedicate energy to sharpen their mental maths and learn shortcuts at the start of their preparation. This is essential because more than 50% of questions in the test involve maths.

This small initial time investment seems to provide them with the confidence they need to perform computations quickly and accurately on the day of the test. It's also very useful with their McKinsey interviews after the PST.

As we mentioned previously the type of maths you will have to do is not extremely complicated per se. It is mainly additions, subtractions, divisions, multiplications and growth rate calculations. But the challenge will be to do a LOT of calculations VERY QUICKY and ACCURATELY. You won't have time to double check your computations. So being confident that they are right first time will be a HUGE advantage.

The first part of the McKinsey PST Training Programme contains maths videos to help you review the basics of mental calculations as well as learn some useful shortcuts. In addition, it also includes a calculation workbook which you will be able to use to practice computations.

5.3 Master a fast and consistent answering method

Most candidates would be able to pass the test if there wasn't a time limit. Once you've reviewed basic maths and are confident in your quantitative skills again, you need to start thinking about how you can answer MORE questions in LESS time.

In our experience, the key to achieve this is to ALWAYS use the same step-by-step method to answer questions. When the team at IGotAnOffer was preparing for the PST we were really struggling to answer all questions in less than 60 minutes initially. But at some point, we decided to try to always use the same approach, and it made a HUGE difference.

There are two benefits to always approaching PST questions in a consistent way.

First, using a structured and consistent answering method enabled us to develop HABITS. After a while, answering PST questions became second nature. It started to feel like a routine and we therefore gradually became more comfortable and much FASTER.

The second benefit is psychological. Always using the same step-by-step approach means that when you walk in the room on the day of your PST you ALREADY KNOW what you are going to do. There is no improvisation. You just apply a system that you have mastered and are comfortable with. This made a BIG difference for us. And the candidates we work with today also say it really helps them to be CONFIDENT on the day of the test.

The second part of the McKinsey PST Training Programme is where we teach the step-by-step system we call the "IGotAnOffer method". We've refined this approach over the years. And some of the best universities around the world including Harvard also recommend using it today.

5.4 Practice on sample tests

Finally, once you have developed a consistent way of answering PST questions you should practice on PST sample tests. There two important tips you should apply when practicing on sample tests.

First, you should practice in REAL CONDITIONS. This means your should print your PST tests, only allow yourself 60 minutes, and no calculator and scrap paper. This might sound like an obvious tip but it's actually quite hard to really stick to this in practice. The reason it's so important to do this is that it will make things feel more familiar on the day of your test.

And second, you should STUDY YOUR MISTAKES IN DETAIL. In our experience practicing on 6 PST tests (e.g. 3 from McKinsey, 3 from IGotAnOffer) is more than enough to pass the test. It's better to practice on 6 tests and to get the most out of each of them by studying your mistakes in detail than to practice on 15 different tests but to not get much out of any of them.

The McKinsey PST Training Programme contains 3 tests made up of 26 questions each. Past candidates who have used these tests often report that they are the closest to the actual PST test that are available on the Internet (you can have a look at the review section of the programme for testimonials). We have also enriched these tests with detailed answers and special tips to make you faster.

Additional resources

If you would like to learn a step-by-step method to consistently crack the McKinsey PST questions you can get started below. More than 80% of students who use our McKinsey PST Training Programme are successfulWe know this because we give half their money-back to candidates who aren't.

 McKinsey PST Training Programme

 

Any questions about the McKinsey PST?

If you have any questions about the McKinsey PST, do not hesitate to ask them below and we will be more than happy to answer them. All questions are good questions, so go ahead!

The IGotAnOffer team