42.1 What to Record After Every Case
Complete your log shortly after each practice case while the experience is still fresh.
Record basic information such as:
- Case: Topic and case type.
- Date: When you practiced.
- Partner: Who interviewed you, if applicable.
- Overall performance: Brief assessment of how the case went.
- Strengths: What worked well?
- Weaknesses: What caused difficulty?
- Feedback: What did the interviewer identify?
- Next action: What specific skill will you practice?
Keep it concise: The log should help your preparation, not become another lengthy assignment.
42.2 Recording Your Mistakes
Do not simply write “math mistakes” or “bad structure.” Describe the error precisely.
Weak entry: “I struggled with math.”
Better entry: “I set up the revenue calculation correctly but lost a zero when converting from millions to billions.”
Then identify the likely cause and correction.
Cause: I stopped tracking units during the calculation.
Correction: Write units beside every input and final result.
Specific mistakes lead to specific drills.
42.3 Identifying Recurring Patterns
A single mistake may not matter much. The same mistake appearing in four cases does.
Review your log regularly and look for repeated problems such as:
- Generic structures.
- Failure to prioritize.
- Arithmetic errors under pressure.
- Weak exhibit interpretation.
- Long, unstructured answers.
- Failure to synthesize findings.
- Recommendations without quantified support.
Priority: Recurring, high-impact weaknesses should drive your preparation plan.
42.4 Tracking Quantitative Errors
Separate different types of quantitative mistakes because they require different solutions.
Useful categories include:
- Setup error: You chose the wrong equation.
- Arithmetic error: The equation was correct but the calculation was wrong.
- Unit error: You confused percentages, millions, billions, or time periods.
- Interpretation error: You calculated correctly but drew the wrong conclusion.
- Speed issue: You arrived at the answer but took too long.
If most errors involve units, practicing harder arithmetic is unlikely to solve the problem. Train the specific weakness instead.
42.5 Tracking Structural Weaknesses
Structure problems also need precise diagnosis.
Record whether your structure was:
- Incomplete: You missed a major driver.
- Overlapping: Several branches covered the same issue.
- Generic: It was not tailored to the client.
- Too detailed: You created unnecessary complexity.
- Unprioritized: You could not explain where to begin.
Useful habit: Rewrite weak structures after the case. Creating a better version while the problem is still fresh reinforces the lesson.
42.6 Tracking Feedback from Partners and Coaches
Keep external feedback separate from your own assessment so you can compare the two.
You might believe your main weakness was math while several interviewers consistently identify communication as the larger problem.
Record feedback as specifically as possible:
Instead of: “Be more concise.”
Record: “My exhibit answer took two minutes because I described every category before giving the headline.”
When several independent partners give similar feedback, treat that pattern seriously.
42.7 Creating Targeted Drills
Every important weakness in your log should eventually produce an action.
For example:
- Weak prioritization: Complete ten structure drills and state which branch you would investigate first.
- Slow percentages: Practice percentage calculations for ten minutes daily.
- Weak synthesis: Practice giving 30-second conclusions after exhibits.
- Long answers: Record responses and repeat them in half the time.
Improvement cycle: Mistake → Diagnosis → Drill → Retest.
This is far more effective than simply adding another full case.
42.8 Measuring Improvement over Time
Your log should show whether weaknesses are becoming less frequent.
Review it weekly and ask:
- Which problems have improved?
- Which problems continue to repeat?
- Which new weaknesses have appeared?
- Am I requiring less interviewer guidance?
- Is my performance becoming more consistent?
Measure trends: One excellent or poor case matters less than your performance across several cases.
You should gradually see old weaknesses disappear from the log or become less severe.
42.9 Knowing When to Stop Practicing
More practice is not automatically better. Once your interviews approach, excessive case volume can produce fatigue without meaningful improvement.
You may be ready to reduce practice when:
- Performance is consistent: Several recent cases have been solid across the major dimensions.
- Recurring weaknesses are controlled: Your previous major problems no longer appear frequently.
- Recovery is reliable: Mistakes no longer derail the case.
- Feedback is increasingly minor: Partners are identifying refinements rather than fundamental problems.
Near the interview, prioritize maintaining fluency and confidence rather than attempting to rebuild your entire approach.
Final principle: A case practice log converts experience into deliberate improvement. Record specific mistakes, look for patterns, create drills that address the underlying causes, and track whether those problems disappear over time. The goal is not to accumulate practice hours or cases. It is to make each case inform what you should practice next until strong performance becomes consistent.
