Most PEI prep dies on the third follow-up. Candidates write a polished STAR paragraph, rehearse it once, and freeze when the interviewer asks what happened in the next meeting. The Personal Experience Interview is not a speech contest. It is a probe session, and the sheet rewards ownership you can defend under pressure, not a highlight reel.
That is the thesis for this piece: stop collecting "good stories" and start building a story bank that survives the ladder of follow-ups McKinsey and every other firm run. I wrote the free workbook at /resources/pei-fit-workbook for exactly that job. After you finish this article you will know what is inside it, how to use it beside McKinsey's own interviewing page, and how to pressure-test the bank on the timed simulator at /behavioral.
What the interviewer is actually scoring
When I score a fit round, I am not grading eloquence. I am answering one question: would I put this person in front of a client on Thursday. McKinsey names the exercise PEI and publishes themes on its careers interviewing page. As of the firm's public guidance, candidates should come with two detailed personal examples for each theme, focused on their specific role and the actions that mattered. Theme labels have shifted over the years; the substance has not. BCG frames a parallel skills interview around experience, motivation, and how you work with people. Bain's interviewing guidance likewise expects behavioural depth, not a memorized script.
The workbook maps stories to four McKinsey signals I use as the working set: leadership, personal impact, drive, and growth / adaptive. If your invitation email uses slightly different words, map your bank to the invitation. Do not invent a fifth dimension because a blog said so.
| Signal | What I listen for | Passes | Dies |
|---|---|---|---|
| Leadership | You moved a group without needing the title | You changed the plan and people followed | "I was team lead" on a slide |
| Personal impact | You changed one person's mind | A named objection in a named meeting | "I am good with people" |
| Drive | You wanted a hard thing and paid for it | Months of push, a miss you owned | "I am passionate" |
| Growth / adaptive | You changed how you work after being wrong | The second system you built | A training certificate |
McKinsey's own careers blog has said the quiet part out loud: stop drowning the interviewer in setup, and stop hiding behind "we." Their Thursday Tip tells candidates to focus on the role they played and the critical actions, not the team's collective biography. That single habit separates PEI-ready stories from résumé narration.
What Ned put in the workbook (and what he did not)
I wrote the PEI and fit workbook as a written-out PDF resource, not a quiz and not a chatbot. It lives at /resources/pei-fit-workbook. Inside, by design:
- Four signal definitions with pass / fail examples
- A 12-slot story bank (one-sentence placeholders you expand later)
- Compressed STAR worksheets (situation in one breath; action as about 60 percent of the airtime)
- A follow-up ladder of four probes you pre-load for every story
- 42 prompts grouped by leadership, personal impact, drive, growth, plus firm-flavour variants
- A self-review rubric scored 1–5 on five checks
That is the inventory. There is no secret answer key, no firm affiliation claim, and no promise that filling the PDF equals an offer. BCG and Bain will not ask "which McKinsey signal is this," but the same bank covers their behavioural rounds because ownership, conflict, grit, and learning travel.
The 12-slot bank is the real product
Guides talk about "eight stories, two per dimension." McKinsey's public advice is two examples per theme, which is eight if you treat each theme once. I want twelve one-liners before you expand anything, because interview day kills one or two stories when the prompt does not fit. The workbook's slots are concrete enough that you cannot cheat with "I worked hard":
- Changed someone's mind when they strongly disagreed
- Led without formal authority
- Led a team through an ambiguous problem
- Set an ambitious goal and missed it
- Developed someone who was struggling
- Failed and changed the system, not just your mood
- Delivered under an ugly constraint
- Ethical or values tension you actually felt
- Structured an ambiguous problem with incomplete data
- Grit over months, not a heroic weekend
- Influenced a commercial or pricing call
- Delivered an unwelcome recommendation and stayed in the relationship
Undergrad with no "client"? Use a society, a lab, a store, or a family business. The test is ownership, not letterhead.
Worked example: score a story the way the sheet does
Take a candidate talking about a campus fundraising drive. Bad version, roughly what I hear in first rounds:
We raised more money than last year. I was on the committee. We sent emails and held a gala. It went well and I learned a lot about teamwork.
Now score it on the workbook's five-point rubric (anything under 4 gets rewritten):
| Check | Score | Why |
|---|---|---|
| Decision owned in first 20 seconds | 1 | No decision; only a project |
| "I" vs "we" | 1 | Entirely "we" |
| Number in the result | 2 | "More than last year" is not challengeable |
| Second layer ready | 1 | No meeting, objection, or evidence |
| Partner-at-dinner tone | 2 | Performance, not a colleague story |
| Average | 1.4 | Rewrite before you practice aloud |
Rewrite with the same facts, owned:
Situation: March, three weeks before the gala, we were at 62 percent of a $40,000 goal. Task: I owned the corporate outreach list. Action: I called the two largest sponsors who had gone quiet, offered a smaller table package when the full ask stalled, and cut the print brochure to free $1,800 for ads. Result: we finished at $41,200; the second sponsor closed after I sent a one-page ROI note. Differently: I would have set a mid-month go / no-go on the brochure two weeks earlier.
Same event. Different score. Rough average on the rubric: 4.2. The difference is not adjectives. It is a decision, three specific moves, a number, and a second layer ready for the ladder.
The follow-up ladder (where most banks fail)
They will ask what you did, more than once. The workbook pre-loads four answers for every story:
- The next meeting
- The strongest objection
- The number or evidence that changed the decision
- What you would do differently, and why
If you cannot answer item 4 without collapsing into "I would have worked harder," the story is still a highlight reel. Item 4 is also where growth / adaptive stories live: the second system, not the certificate.
Ned's rule. If you cannot name the next meeting, the strongest objection, and one number before you open your mouth, do not bring that story into a PEI. Write it out of the bank or expand it until those three answers are boringly specific.
How to use the workbook with McKinsey's page and the timer
Do not treat the firm's careers page, the PDF, and the simulator as three optional hobbies. Sequence them:
- Read McKinsey's interviewing page once so you know the public ask: PEI plus problem-solving, two examples per theme, detail on your role.
- Open /resources/pei-fit-workbook and fill the 12 one-liners in one sitting. Ten minutes. No polishing.
- Expand six into STAR using the worksheets. Force action into three beats: the meeting, the objection, the move.
- Run each of the six against the 42 prompts. If a prompt does not hit a story in ten seconds, that slot is empty.
- Score yourself on the rubric. Rewrite anything under 4.
- Take the weakest story into /behavioral. The timed PEI simulator is open during CoachNed's free week (everything is open for seven days, no card; then $120 for a recruiting season or $49 a month). Use the clock. Scripts that sound fine in a notebook fall apart at ninety seconds under follow-ups.
BCG's interview process and Bain's interviewing page do not copy McKinsey's four labels. Keep the same bank. Change the opening sentence to match the firm's language ("tell me about a time you influenced without authority" instead of naming a signal). The ladder stays.
A one-week plan with real hours
| Day | Minutes | Output |
|---|---|---|
| Night 1 | 20 | 12 one-liners in the bank |
| Night 2 | 45 | Six STAR drafts on paper |
| Night 3 | 30 | Ladder answers for each of the six |
| Night 4 | 25 | Rubric scores; rewrite the two weakest |
| Night 5 | 20 | One timed rep on /behavioral |
| Night 6 | 30 | Rewrite from the debrief; coffee-chat version (90 seconds) and PEI version (~3 minutes) of the same story |
That is under three hours across a week. Candidates who instead reread frameworks for three hours still fail the third probe.
Practice this tonight
Open the workbook. Write twelve one-sentence stories into the bank. Do not expand yet. Then pick the emptiest signal (usually growth / adaptive) and write one full STAR with the ladder pre-loaded. Tomorrow, run that story once on /behavioral. If you want a graded case after fit, /start is a five-minute first rep with no account required.
CoachNed is not affiliated with McKinsey, BCG, Bain, Deloitte, or any firm named here.
Frequently asked questions
Is the CoachNed PEI workbook free?
Yes. The written workbook at /resources/pei-fit-workbook is a free public resource Ned wrote. The timed PEI simulator at /behavioral is open during the free week along with the rest of the product.
How many stories do I need for McKinsey PEI?
McKinsey's public interviewing page asks you to prepare two personal examples for each of its published themes. Treat that as a floor of eight. The workbook uses twelve slots so you have spares when a prompt does not fit your primary story.
Does the workbook work for BCG and Bain fit interviews?
Yes for the bank, not for the labels. BCG and Bain run behavioural and skills conversations without McKinsey's four named signals. Keep the same stories, drop the signal names in the room, and keep the follow-up ladder.
How long should a PEI answer be before follow-ups?
Aim for roughly ninety seconds to three minutes for the opening pass, then let the interviewer drive. If your opening alone runs past three minutes, you are still narrating setup. Cut situation to one breath and spend the airtime on action and result.
What is the difference between the workbook and McKinsey's careers page?
McKinsey's page states what the firm listens for and how to prepare at a high level. The workbook is the writing surface: twelve slots, forty-two prompts, STAR sheets, a follow-up ladder, and a self-review rubric. Use both. Neither replaces timed practice.
Sources
- Interviewing at McKinsey — official PEI overview and guidance to prepare two detailed examples per theme. Checked 2026-09-24.
- Thursday Tip: talk about your contributions — McKinsey careers advice to focus on "I" and critical actions, not team "we." Checked 2026-09-24.
- BCG consulting interview process — skills / behavioural interview as a parallel to PEI. Checked 2026-09-24.
- Bain interviewing — behavioural interview expectations across roles. Checked 2026-09-24.