Your degree is not the handicap. The firms say so on their own careers pages, and they mean it: they recruit law, medicine, engineering, physics, and the rest because those minds travel. What I see fail in the room is not a missing transcript line. It is a missing dictionary of about a dozen business words, plus three arithmetic habits that business majors absorbed by osmosis. Close those two gaps and your science or humanities training becomes an advantage the scoring sheet can hear.
This piece gives you the firms' own language on backgrounds, the short vocab and habits list, a six-week plan that does not pretend you need a mini-MBA, and one fully worked translation from a lab habit into case points. After you finish, you should know exactly what to practice this week and what to ignore.
The firms hire you on purpose
Start with primary sources, not folklore.
McKinsey's interviewing page states it seeks problem-solvers "from a wide range of disciplines—whether you come from law, medicine, engineering, or another field entirely." That is not marketing fluff aimed at business schools. It is the firm's public description of who it wants in the funnel.
BCG Switzerland's non-business recruiting page goes further with a number: "half of our consultants never studied business." The same page lists engineering, biochemistry, physics, medicine, and computer science as valued backgrounds, and it runs a dedicated Consulting Essentials Training for people without a business degree once they join. In the United States, BCG's Associate recruiting FAQ says undergraduate and non-MBA master's students "from all fields of study and backgrounds are welcome to apply."
Bain's Associate Consultant Internship posting lists "All disciplines/degrees are welcome" among the typical requirements, and its FAQ says you need no prior consulting experience and should apply "no matter your area of study or background."
So the interviewer is not waiting for you to apologize for majoring in chemistry or classics. The sheet rewards structure, clean math, judgment under ambiguity, and a crisp recommendation. Your job is to sound like someone who can sit next to a CFO for an hour without needing a translator.
The real gap: twelve words and three habits
You do not need corporate finance, GAAP, or a semester of strategy. You need to hear and use the following without pausing.
| Word | What it means in a case | Say it this way |
|---|---|---|
| Revenue | Price × volume (sometimes × mix) | "Sales dollars before cost" |
| Volume | Units, visits, seats filled | "How many times they sold it" |
| Mix | Share of high- vs low-price items | "Which products or customers grew" |
| Variable cost | Moves with volume | "Cost per unit that scales" |
| Fixed cost | Does not move with volume in the horizon | "Rent, salaries, overhead for now" |
| Margin | Profit as a share of revenue | "What is left after cost, as %" |
| Contribution | Price minus variable cost per unit | "Cash per unit toward fixed costs" |
| Breakeven | Volume that covers fixed costs | "How many units until we stop losing money" |
| Segment | A customer or product slice that behaves differently | "Which group moved" |
| Share | Company revenue ÷ market revenue | "Our slice of the pie" |
| Utilization | Actual output ÷ capacity | "How full the asset is" |
| Payback | Investment ÷ annual profit (rough) | "Years to earn the spend back" |
Memorize the left column. Practice saying the right column out loud until it feels ordinary. That is ninety percent of the "business basics" panic.
Then install three arithmetic habits. Business majors already have them; you can learn them in a weekend and reinforce them for five weeks.
- Equation before digits. Write
profit = revenue − costorbreakeven units = fixed ÷ contributionbefore you touch a number. Interviewers grade setup. Wrong arithmetic with a correct setup is recoverable; floating numbers without a structure are not. - Units in every line. Say "dollars per visit," "visits per week," "weeks per year." Non-business candidates often do correct math on the wrong object and never notice.
- One-sentence implication. After every calculation, add what it means for the decision: "So contribution is $4; at 2,000 visits we clear only $8,000 against $12,000 rent — we are short $4,000." Silence after a number is how you leak points.
Ned's rule. If you can define margin, contribution, and utilization in one sentence each, and you always name the units before the arithmetic, you are past the non-business deficit I actually see on the sheet. Everything else is practice volume.
One translation: lab method into case points
Here is the habit most science majors already own and rarely use in the room: control the variable. In a lab, you change one thing, hold the rest fixed, and read the result. In a case, that is how you isolate a profit driver.
Prompt (original). HarborGlow operates three mid-size aquariums in coastal cities. Last year revenue rose 6%, but profit fell $1.2M. Management wants the root cause and whether to raise ticket prices 8% next season.
A weak non-business answer sounds like a literature review: tourism trends, climate, school-group bookings, gift-shop strategy, competitor theme parks. Interesting. Not a structure.
A strong translation uses the lab habit:
Hypothesis frame (what a scientist already does). Profit fell while revenue rose, so either costs rose faster than revenue, mix shifted toward lower-margin visits, or both. I will hold volume fixed in my mind, check price and mix, then check cost buckets — one variable at a time.
Structure the interviewer can score.
| Branch | What I check first | Control / hold fixed |
|---|---|---|
| Revenue quality | Ticket price, visit mix (families vs school groups vs tourists), ancillary spend | Total visits held constant while I inspect mix |
| Cost | Animal care, energy, staffing, marketing | Revenue held constant while I inspect cost growth |
| Capacity | Peak-day utilization, empty midweek slots | Ask whether volume growth came from discount days |
Worked numbers (you can reproduce these). Suppose total visits were 900,000 both years. Average ticket rose from $28 to $30 (+7%), so ticket revenue alone explains most of the 6% sales lift. Gift-shop attach rate fell from 40% of visitors spending $12 to 32% spending $11. Ancillary revenue change:
- Year 1: 900,000 × 0.40 × $12 = $4.32M
- Year 2: 900,000 × 0.32 × $11 = $3.17M
- Drop: $1.15M
If animal-care and energy rose another $0.4M, you have already explained more than the $1.2M profit miss without inventing a tourism crisis. The recommendation on an 8% ticket hike follows from contribution, not from vibes: if contribution per visit is roughly $18 and demand is elastic among school groups, a blanket hike may shrink the wrong segment. Test the hike on tourist tickets only; protect school-group volume.
That is the translation. You did not become a business major. You ran a controlled comparison and narrated it in margin language. Humanities majors do the same move with argument structure: claim, evidence, counterargument, residual risk — which maps cleanly onto answer-first synthesis.
Six weeks, not a second degree
Treat this as a skills calendar. Adjust intensity, not the sequence. Rough planning range from what I see work: about 50–70 focused hours across six weeks if you already think in structures (engineering, physics, formal logic); closer to 70–90 if your background is heavy on prose and light on mental arithmetic. Those are Ned's estimates, not firm guarantees.
| Week | Focus | Concrete output |
|---|---|---|
| 1 | Vocab + habits | Flash the twelve words daily; 20 equation-first drills on paper (no cases yet) |
| 2 | Profitability only | 6–8 profitability cases; every debrief must name margin, mix, or fixed vs variable |
| 3 | Market sizing + charts | 5 sizings with unit discipline; 5 exhibits where you state one implication, not a data tour |
| 4 | Market entry / ops | 6 cases; force a capabilities-and-economics branch before you brainstorm |
| 5 | Full mocks under time | 8 cases with a partner or AI interviewer; score yourself on setup, units, synthesis |
| 6 | Weak-spot loops | Only the skill that still leaks points (usually synthesis or chart implication for STEM; math for humanities) |
Quality beats volume. Ten cases with a forced debrief beat thirty silent ones. If you only have four weeks, compress weeks 2–4 and keep week 1 intact — skipping the vocab week is how people look sharp and then freeze on "contribution margin."
For a skill-based calendar that scales beyond six weeks, use the consulting interview prep timeline. For the formula sheet that matches the table above, keep the case interview formulas guide open while you drill.
What the scoring sheet rewards (and ignores)
I stop listening when a candidate delivers a topic essay. I lean in when they:
- Restate the decision in one line ("find why profit fell, then decide on the price hike").
- Open two to four MECE branches tied to that decision.
- Set an equation before arithmetic.
- Drive to a recommendation with a risk and a next fact to check.
I ignore pedigree theater ("as a molecular biologist…") unless it earns a sharper structure or a better sanity check. The sheet does not give bonus points for your major. It does give points when your major's method shows up as cleaner isolation of drivers.
CoachNed is not affiliated with McKinsey, BCG, Bain, Deloitte, or any firm named here.
Practice this today
Do one HarborGlow-style profitability case out loud. Force yourself to use at least four words from the table and to state units on every line. Then run a timed structure drill and a math drill so the habits stick under pressure.
Everything on CoachNed is open for seven days with no card; then $120 for a recruiting season or $49 a month. Start with the five-minute first rep at /start, or take the live voice case at /interview when you want a full debrief.
Frequently asked questions
Do consulting firms hire non-business majors?
Yes. McKinsey, BCG, and Bain state on their careers pages that they recruit across disciplines, and BCG's non-business page claims roughly half its consultants never studied business. Your interview performance matters more than your department.
How long should a non-business major prep for case interviews?
Plan on about six weeks and roughly 50–90 focused hours, depending on how comfortable you already are with mental math. Front-load vocabulary and equation-first habits in week one so later cases teach judgment instead of terminology.
What business concepts do I need if I did not study business?
You need a compact set: revenue, volume, mix, fixed and variable cost, margin, contribution, breakeven, segment, share, utilization, and payback. That list covers the large majority of first-round math and structure. Skip GAAP and valuation until you have an offer and a training week.
Should I take accounting or finance classes before recruiting?
Usually no. A short self-study of the vocab table plus drilled cases beats a semester of accounting for interview purposes. Firms that care about non-business hires often run their own essentials training after you join.
How do I turn a science or humanities skill into case performance?
Map the method, not the subject matter. Scientists: control one variable at a time when profit and revenue move in opposite directions. Humanities: claim, evidence, counterpoint, residual risk as your synthesis template. Say the business nouns while you run the method you already trust.
Sources
- Interviewing at McKinsey — firm statement that it seeks candidates from law, medicine, engineering, and other fields. Checked 2026-09-24.
- BCG Switzerland: join with any background — claim that half of BCG consultants never studied business; lists STEM and medical backgrounds; notes Consulting Essentials Training for non-business hires. Checked 2026-09-24.
- BCG United States Associate job opportunities — eligibility for undergraduates and non-MBA master's students from all fields of study. Checked 2026-09-24.
- Bain Associate Consultant Internship — "All disciplines/degrees are welcome"; FAQ encourages applicants regardless of area of study. Checked 2026-09-24.