Candidates report that Casey usually opens with a data question: which few datasets would you request? It looks like a warm-up. It's the question that decides whether the rest of the case makes sense to you.
This lesson gives you one method for it, worked on the free Union Commercial Bank case. Play the case first if you can: lessons 2 to 5 walk through its answers.
The method, in 4 steps
Write the hypothesis
One sentence a dataset could prove wrong. Not "pricing is a problem", but "similar clients pay different prices because RMs discount".
Pick the outcome
The number the hypothesis is about.
Pick the controls
What legitimately moves that number, so you compare like with like.
Pick the suspect
The one variable that measures the cause you're testing. Everything else waits, however interesting.
Worked example
Union Commercial Bank, question 2
Example · practice contentPlay the free case first (40 min)
UCB's 200 Relationship Managers (RMs) set loan prices with wide discretion. Management suspects they over-discount to win deals. Your project leader wants to compare loan pricing for clients with similar risk levels and business size.
Which four data points are most critical for this analysis? Select 4.
Show the workingTry it first. The method, step by step, then the answer.
- HypothesisSimilar clients pay different prices, and RM discounts explain the gap.
- OutcomeA, the interest rate each client pays.
- ControlsB, risk (PD), and F, loan size: the brief names both as what makes clients "similar".
- SuspectH, the discount each RM gave. It measures discretion directly.
- DroppedC is a list, not a number. D matters later, for the price model, not for this comparison. E is an average, and an average hides the spread you're testing. G is outside UCB.
Answer A, B, F and H.
Recap · Lesson 01
Pause here
- Hypothesis first: One sentence the data could prove wrong.
- Outcome, controls, suspect: That's usually three or four picks. Stop there.
- An average hides a spread: If the question is about dispersion, ask for the row-level number.
Tonight · free40 min
Play Union Commercial Bank, start to finish
The free case: 12 questions on a 40-minute clock, ending with the video step, Casey-style. Play it before lesson 2, so the next four lessons are about answers you've already given.
Open it freeSources4 numbered sources, labeled by type
- DrillCase guide DrillCase: BCG Casey online case, the complete guide: last verified 23 Sep 2026.
- DrillCase guide DrillCase: The Casey dataset-selection question, with six worked examples
- DrillCase guide DrillCase: Union Commercial Bank, the free Casey-style demo case: question text and answer key.
- Prep site Hacking the Case Interview: BCG Casey (updated 19 Mar 2026): "choose the fewest options that cover the most ground".
Independent practice. Not affiliated with BCG.