I applied online. The process took 1 week. I interviewed at McKinsey & Company (London, England)
Interview
This role was Data Scientist - Life Sciences and they were looking for someone with 2+ years of experience in stats, math, comp sci or equivalent + research experience.
I received an automated email to say I'd been invited to take a HackerRank Assessment. The assessment was 2 hours long with 3 questions. The first two questions were advanced competitive programming puzzles that required obscure optimisations in order to pass all test cases. The HackerRank platform shows you only a small number of the total test cases and I found that my code passed all the ones I could see but was failing on the ones I could not see so it was very difficult to optimise as you're trying things totally blind. The third question was to build a machine learning model to make predictions on a data set (the data needed loading, predictions needed saving to a csv and a prediction error threshold was set).
I'm not sure if it's just me but this test felt inappropriate for the job role. The two advanced programming puzzle was completely unrelated to any of the skills needed for the job. The third question was relevant but to only have two hours total when you needed to complete the puzzles was not enough time to actually build a decent model. I finished the first question, passed 6/13ish test cases on the second and then didn't have time for the only relevant question. Within minutes of submitting I recieved an email saying they wouldn't be taking my application further.
Overall, I felt that this initial screening assessment was completely unreasonable for the time frame provided and the two algorithmic puzzles were irrelevant to the job role. The immediate failure email made this quite the demoralising experience overall and I think a bit of a waste of time.
Interview questions [1]
Question 1
They asked me solve an advanced algorithmic puzzle
Mediante un phone screen y tambien con un examen de HackerRank para poder medir las cualidades de uno y asi poder obtener un assessment real sobre las habilidades de uno
I applied through a staffing agency. I interviewed at McKinsey & Company (Madrid) in May 2026
Interview
Largo y con muchas exigencias, es un proceso a preparar pese que está bien guiado no sabes por qué tipo de sector va a llegar y es complejo, muy demandante y largo
Interview questions [1]
Question 1
Tres personal experience interview, tres business cases, una technical experience interview.
I applied online. I interviewed at McKinsey & Company (New York, NY) in Apr 2026
Interview
1. Hackerrank OA
2. Recruiter Screen
3a. Initial Round - Coding Exercise + PEI Question
3b. Initial Round - Case Study
4a. Final Round - Case Study + 2 PEI Questions
4b. Final Round - PEI Question + TEI Questions
The final round was in person; all others were virtual. My recruiter was extremely communicative and helpful throughout the process. Final round with partners was less structured.
1
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