For teachers and counsellors
A guide for staff preparing economics, E&M and PPE applicants. By Luke Masom, EconCoaching.
Oxbridge economics interviewers are not checking what a student knows. They give a problem the student has not seen and watch how they think: whether they reason out loud, use the interviewer's hints, test their own ideas and change their mind well. A good mock recreates that. Let the student work, interrupt with a hint or a changed assumption, and watch what they do with it.
Mark three things, in this order. The first two decide the score; the third explains it to the student.
| Criterion | 5 looks like |
|---|---|
| Reasoning | Builds an argument step by step, and each step follows from the last |
| Economic concepts | Uses the right idea at the right moment, correctly, without name-dropping |
| Adapting | Uses your hints and new information, and changes course when the argument breaks |
| Numeracy | Handles numbers accurately and says what they mean (leave out if no numbers came up) |
| Communication | Clear, structured, thinks out loud, ends on a judgement |
| Technique | What it sounds like |
|---|---|
| Narrate | Says what they are doing and why, including when stuck |
| Pin it down | Restates the question and defines vague terms first |
| Start simple | Begins with the obvious point, an extreme case or small numbers |
| Assume out loud | Chooses a simplification on purpose and says what it rules out |
| Take the hint | Uses your prompt visibly and says what it changes |
| Check it | Tests the answer before committing |
| Land, then defend or update | Ends on a judgement; holds it or changes it openly under challenge |
All three are widely reported interview questions. Ask the question, give the student a minute, then use the prompts.
"Water keeps us alive and diamonds are mostly decoration. Why, then, does a diamond cost so much more than a litre of water?"
Key points to mark for question 1 (2, 1 or 0 each):
| # | Key point |
|---|---|
| 1 | Separates the total value of water from the value of one more litre |
| 2 | Diamonds are scarce relative to demand, so one more is valued highly |
| 3 | Price reflects the value of the last unit bought, and the cost of supplying it |
| 4 | Supply side: water is cheap to supply; diamond supply is costly and has been controlled |
| 5 | Part of a diamond's value comes from being expensive (a signal) |
| 6 | Lands on a judgement: the paradox disappears once you reason about the next unit |
The key points for questions 2 and 3 are in Ceteris, with those for 430 other questions.
"I give you £100 and ask you to offer some of it to another person. If they accept, you each keep your share. If they refuse, neither of you gets anything. How much would you offer?"
"Graduates in the UK earn much more on average than people without degrees. A politician says this proves going to university raises your earnings. Do you agree?"
| Score | Note from the mock | |
|---|---|---|
| Key points reached | __ of __ | |
| Reasoning (1–5) | ||
| Economic concepts (1–5) | ||
| Adapting (1–5) | ||
| Numeracy (1–5, or n/a) | ||
| Communication (1–5) | ||
| Techniques seen | ||
| Techniques missing | ||
| Overall (1–5) |
Agree one thing for the student to practise before the next mock.
Marking one mock this way takes a teacher 20–30 minutes to run and 10–15 to mark, and needs key points for every question asked. For 12 applicants doing three mocks each, that is around 24 hours of staff time (an example; your numbers will differ).
The Ceteris AI Interviewer runs the same kind of interview out loud, at any time, and marks it the same way in a few minutes:
Students can practise between your mocks as often as they need, and keep your staff's time for the final run-through, where a person matters most.