Quant Interview Foundations Checklist
A practical checklist for quant interview foundations across probability, expected value, statistics, mental math, coding, and communication.
Candidates checking readiness before moving into mocks or firm-specific prep.
Probability and counting
You should be comfortable defining sample spaces, using complements, separating ordered from unordered outcomes, handling replacement, and conditioning on new information. If cards, dice, and coins feel like unrelated topics, the foundation is not yet stable.
Expected value and statistics
You should know linearity of expectation, basic variance and covariance intuition, common distributions, sampling error, and how to explain uncertainty in data. For trading roles, expected value should connect naturally to fair prices and bet sizing.
Mental math and estimation
You do not need perfect speed, but you need reliable arithmetic under pressure. Fractions, percentages, expected payoff arithmetic, and round-number estimation should be accurate enough that they support the reasoning instead of derailing it.
Coding and implementation
For research and developer roles, foundations include clean loops, data structures, complexity, tests on small examples, and edge-case handling. Even trading candidates benefit from being able to reason through simulations or simple algorithms.
Communication readiness
You should be able to state assumptions, explain why a method applies, check the answer, and adjust when the interviewer changes a condition. Communication is not polish added after the math; it is how the interviewer sees the math.
Common mistakes
The checklist is not a reason to delay practice forever. If most foundations are stable, move into mixed sets and mocks. If one foundation repeatedly breaks, repair it directly before adding harder variants.
Practice the pattern
Use the LeetQuidity curriculum and calibration to turn this topic into a focused practice plan.