The CoachNed drill engine grades six MBB skills (structure, brainstorming, math, market sizing, exhibits, synthesis) inside a full consulting-interview prep platform powered by AI. The free tier gives you 1 full AI-graded case, daily drill practice, one free resume review, plus the first two BCG Casey-style simulator questions with no account.
Updated Jul 18, 2026. Reviewed by Ned.
The CoachNed drill engine grades six MBB skills with AI feedback: Structure, Brainstorming, Case Math, Market Sizing, Exhibits, and Synthesis. Each drill targets 30-90 seconds and matches the dimensions the full-case seven-dimension scorecard uses. It is one surface in CoachNed's full consulting-interview prep platform powered by AI, which includes 57 active practice cases, a 600+ drill bank, two online assessment simulators including a BCG Casey-style simulator with 10 original cases and the first two questions free with no account plus a CCA-style simulator, behavioral and McKinsey PEI practice, Learning Mode, a free consulting resume grader, an application tracker, and a free case-book vault. The free tier gives you 1 full AI-graded case, daily drill practice, one free resume review, plus the first two BCG Casey-style simulator questions with no account. It is the daily-rep complement to weekly graded cases.
The Six Drills MBB Interviewers Actually Test
Most candidates think there are three case skills (structure, math, synthesis). Real MBB rubrics grade six. The CoachNed drill engine builds each one independently:
1. Frameworks (MECE issue trees).** The structuring rep. You see a case prompt, build a 3-4 branch issue tree, and the AI grades MECE depth, branch quality, and prioritization. Targets the structuring dimension on the full-case scorecard.
2. Brainstorming (creative ideation). Generate ideas under MECE pressure. The AI grades both the creativity (did you go beyond obvious branches?) and the structure (are the buckets MECE?). Used by McKinsey and BCG in nearly every case for "what could explain X?" prompts.
3. Case Math (quick mental math). The math rep most candidates know about. You see a profitability or growth calculation; you have 30-45 seconds; the AI grades formula, staged calculation, units, and business meaning. Start with a free math drill for a worked rep.
4. Market Sizing (estimation logic). Top-down or bottom-up market sizing under timer. The AI grades assumption clarity, sanity-check application, and the final business translation. The structure-most-tested format in McKinsey and BCG first rounds.
5. Exhibit Analysis (charts and tables). Chart and table reading drills. You see a P&L extract or a time-series chart, the AI asks one targeted question, you have 60 seconds. Grading covers correct read plus correct implication.
6. Synthesis. The recommendation rep. You get a case prompt and three pieces of data; the AI gives you 30 seconds to synthesize a recommendation. Grading covers hypothesis-first ordering, support quality, and risk acknowledgement.
How the Drill Engine Connects to Full Cases
The drill engine isn't a separate product silo. Each drill grades against the same dimensions the full-case seven-dimension scorecard uses, so practicing drills compounds toward case performance:
| Drill | Maps to full-case dimension |
|---|---|
| Frameworks | Structuring |
| Brainstorming | Structuring + business judgment |
| Case Math | Math |
| Market Sizing | Math + business judgment |
| Exhibit Analysis | Charts |
| Synthesis | Synthesis + communication |
After a full case at CoachNed practice, AI Coach recommends the specific drill targeting your weakest dimension. Running it the next day is the cheapest rep between cases.
How Often to Drill
The discipline most candidates underestimate is drill cadence. Daily 15-minute reps beat weekend marathons because skills consolidate during the gap between sessions:
Daily 15-minute drill routine
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01Mon (3 min): 1 math drill. Warm up the formula + units habit. Same dimension AI Coach scores in full cases.
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02Tue (3 min): 1 structure drill. Build the MECE muscle. Goal: 3-4 branches, prioritize one.
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03Wed (5 min): 1 brainstorming + 1 synthesis drill. Two complementary structuring tests. Brainstorming widens; synthesis narrows.
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04Thu (3 min): 1 exhibit drill. Chart and table reading reps. Most candidates underweight this dimension.
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05Fri (3 min): 1 market sizing drill. Round out the week. Top-down or bottom-up depending on which format you struggle with.
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06Saturday: 1 full case at /try. Drills feed the case; weekly graded full case validates the work.
That stack covers all six skills weekly with about 17 minutes of drill time. AI Coach pattern detection then routes the drill that becomes Sunday's targeted weak-spot rep.
Try a free typed starter drill
The free tier gives you 1 full AI-graded case, daily drill practice, one free resume review, plus the first two BCG Casey-style simulator questions with no account.
How the Drill Engine Compares to Alternatives
Most candidates evaluate CoachNed's drill engine against three alternatives:
| Tool | Skill coverage | Free? | Grading depth |
|---|---|---|---|
| ★ CoachNed drill engine | All 6 (math, structure, brainstorming, synthesis, charts, market sizing) | Yes (full free tier) | Multi-dimension AI grading on each drill, weak-spot tracking |
| RocketBlocks | Math, charts, structure | Paid only (~$155/yr) | Best-in-class chart drills; flat structuring critique |
| ChatGPT with prompts | All 6 if prompted correctly | Yes | Inconsistent grading, no session memory, no chart drills |
| Management Consulted Black Belt | Math drills (inside the Black Belt program) | Bundled with paid program | Strong math grading, narrow scope |
A reasonable stack: CoachNed drill engine as the daily driver, ChatGPT for unlimited volume during the week (see the ChatGPT prep guide for prompt templates), RocketBlocks layered on if charts specifically are the bottleneck. See Best AI Drill Platform for MBB Prep for the full comparison.
What the Free Tier Actually Includes
The drill engine is one surface in CoachNed's full consulting-interview prep platform powered by AI. The free tier gives you 1 full AI-graded case, daily drill practice, one free resume review, plus the first two BCG Casey-style simulator questions with no account:
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Daily drill reps across the six drill skills, starting from a typed flow like structure or math
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One full AI-graded case scored on the seven-dimension rubric
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One free resume review
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The first two BCG Casey-style simulator questions with no account
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AI grading on every drill: formula, units, business meaning for math; MECE depth for structure; chart-read accuracy for graph and exhibit drills
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Weak-spot tracking activates from drill 2 onward, so patterns surface across sessions
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Drill recommendations from AI Coach after every full case at CoachNed practice
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Free tools hub packages targeted drills alongside the calculators and free PEI workbook
The 600+ drill bank covers structure, case math, market sizing, exhibits, brainstorming, and synthesis, with timed Quick Math alongside it. Signup grants one case credit, so a new reader's first full case can be run in Voice Mode for free; Voice Mode after that needs Pro, club access, or more credits.
Verdict
CoachNed is a full consulting-interview prep platform powered by AI, with 57 active practice cases, a 600+ drill bank across 6 skill types plus timed Quick Math, two online assessment simulators including a BCG Casey-style simulator with 10 original cases and the first two questions free with no account plus a CCA-style simulator, behavioral and McKinsey PEI practice, Learning Mode, a free consulting resume grader, an application tracker, and a free case-book vault. The free tier gives you 1 full AI-graded case, daily drill practice, one free resume review, plus the first two BCG Casey-style simulator questions with no account. The drill engine is the platform's daily skill-practice surface.
Run a math drill or start with a structure drill and pick the skill that scares you most.
Sources and Further Reading (checked June 17, 2026)
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Drill engine: structure starter drill
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Math drill: typed starter drill
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CoachNed free tools hub: /tools
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CoachNed pricing: /pricing
Run a free math drill
Use the CoachNed drill engine inside a full consulting-interview prep platform powered by AI. The free tier gives you 1 full AI-graded case, daily drill practice, one free resume review, plus the first two BCG Casey-style simulator questions with no account.
Related Guides
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CoachNed AI Coach
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Best AI Drill Platform for MBB Prep
Frequently asked questions
What skills does CoachNed's drill engine cover?
Most candidates evaluate CoachNed's drill engine against three alternatives:
Is the drill engine free?
Most candidates evaluate CoachNed's drill engine against three alternatives:
How long does each drill take?
Most candidates think there are three case skills (structure, math, synthesis). Real MBB rubrics grade six. The CoachNed drill engine builds each one independently:
How is the drill engine different from RocketBlocks?
Most candidates evaluate CoachNed's drill engine against three alternatives:
Can I use the drill engine without doing a full case first?
The drill engine isn't a separate product silo. Each drill grades against the same dimensions the full-case seven-dimension scorecard uses, so practicing drills compounds toward case performance:
What does the drill engine grade for math drills specifically?
Most candidates think there are three case skills (structure, math, synthesis). Real MBB rubrics grade six. The CoachNed drill engine builds each one independently: