1. Using a memorized framework
Problem: The structure sounds generic. Fix: Start from the client objective and build buckets that directly explain the decision.
2. Skipping clarifying questions
Problem: You solve the wrong problem. Fix: Clarify objective, geography, timeframe, customer, and success metric before structuring.
3. Dropping units in math
Problem: The interviewer cannot follow the calculation. Fix: Say the equation first and attach units to every number.
4. Describing exhibits instead of interpreting them
Problem: You read the chart but do not explain the implication. Fix: State the headline insight first, then support it with one or two numbers.
5. Ending with a summary
Problem: The final answer recaps facts but does not decide. Fix: Make a recommendation, give two reasons, name one risk, and suggest a next step.
6. Practicing without review
Problem: You repeat the same weakness across cases. Fix: After each rep, write one mistake and one drill for the next session.
How to catch mistakes faster
Record your practice. A transcript makes vague communication obvious: long setup, missing signposts, unclear math, or recommendations that never answer the question. CasePrep helps by giving you spoken practice, recording, transcript review, and feedback after the case.