How To Approach the McKinsey Problem Solving Test

If you’re reading this post you probably have been invited to take McKinsey’s problem solving test (PST). The PST is a 26 question / 1 hour multiple choice test similar in form to the SAT or GMAT exams. It is  the most difficult test of its kind that I have ever taken, mainly because of the time limit and lack of a calculator.

However, it is still very doable IF you make a concentrated effort to prepare for it and change your approach to match the format of the test. You can find example PSTs on McKinsey’s website, here.

I have three (3) suggestions for improving your PST score:

1. Prioritize Questions – Read the questions, and start by only solving questions that take you less than 2 minutes. About half the questions on the test are like this. Skip the longer questions.

2. Don’t Read the Prompt, unless necessary – Read the question instead and try to figure out what information you need to solve this question and where it’s likely to be.

A lot of the PSTs have similar questions and the answers are always in the same place in the prompt (i.e. questions about the CEO’s goals will always have their answers at the end of the first prompt in a section). When you do enough PSTs you start to recognize the pattern.

Also, some of the questions require you to pull information from previous diagrams. That’s why you think about information you need before you go searching. Sometimes it’s not where you expect.

3. Round – Unless two answer choices are very close. Some of the questions require exact answers (i.e. two answer choices are quite close). In that case, don’t round. Otherwise, it’s probably safer / faster to go ahead and round.

If you’re curious how I figured this all out and how I prepared, read below.

Here’s how I approached preparing for the PST:

1. I started by taking a timed sample test. I found that I only got 50-60% of the questions right and that I couldn’t finish the test. From talking to other people this is pretty common.

2. I went back and debriefed every single question. I started by looking at the correct answer for each question and tried to figure out why it was correct and where the information was in the prompt to actually solve that question. (I noticed the information I needed was often in previous diagrams or in the initial prompt).

Then I looked at the wrong answers and tried to figure out why they were wrong, where the information was that disproved each wrong answer choice, and tried to analyze why I chose a wrong answer, if I did.

3. Afterwards I analyzed my weaknesses. I figured out that my biggest weakness the first time I took the test was that I was too slow. I hypothesized that this was because I was trying to read the entire prompt for each section and it was taking too long. (so I decided that it’s better to not read the prompt, unless necessary).

4. The next day I took another PST and this avoided reading the prompts straight away. I started with the question, skimmed the prompts to see if I could find the answer, and answered it if I could. I still got around the same score and didn’t finish.

I repeated the same analysis I conducted in steps 2-3. This time, I realized that my new strategy actually worked pretty well, but the mistake I was making was that I was doing the questions in order and not prioritizing.

Some of these questions took me 10+ minutes, and I concluded they weren’t worth doing because other questions only took 1 minute and every question is weighted equally. Answering every question in order was dragging me down and preventing me from finishing all the easy questions (so I decided to start prioritizing).

5. The day after I took the last PST. This time I skimmed the question, tried to estimate if I could answer it quickly, and if not I skipped it. If I could answer it quickly I decided to figure out what information from the prompt I needed, quickly searched for it, and moved onto the next question.

After analyzing my results in the same way as before I realized I still didn’t finish the test but I got closer than ever before. Also, my score was still the same but this was because I made numerical errors with the math due to not rounding when I could have. (I decided to start rounding if answer choices were wildly different)

Conclusion

I went into the actual PST not feeling confident. However, looking back on it now I actually addressed all of my main weaknesses and was in decent shape. They didn’t tell me what my score was, but I suspect I got at least 70-80% of the questions right, much better than the practice exams.

To sum it all up:

1. Prioritize Questions – Read the questions, and start by only solving questions that take you less than 2 minutes.

2. Don’t Read the Prompt, unless necessary – Read the question instead and try to figure out what information you need to solve this question and where it’s likely to be.

3. Round – Unless two answer choices are very close.

Good luck!

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