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Copy of PM Interview Guide
Interview Guide
Behavioral Questions
Analytics Questions
Estimation Questions
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Estimation Questions
Estimation Questions
Estimation Facts
Experimentation
When evaluating the results of an experiment, what areas do you look at?
Experiment Parameters
How long was the experiment run?
We want to measure immediate impacts + longterm impacts
What percent of users was the experiment run on? How many absolute users was the experiment run on?
We want to make sure that the sample size is representative of the full user-base.
Approach
Clarify the Question & Narrow the Scope
Repeat question
Ask about anything that’s ambiguous
Does “money” mean profit or revenue?
If profit, what costs are we including?
etc.
Does GMAIL mean
gmail.com
or companies that use gmail for hosting their domain?
What is the timing? Last year? Last week? All-time?
US only?
Catalog What You Know (or Wish You Knew)
Remember you can ask for key facts.
Write down everything that you know or think you might need to solve the question
Make list of running assumptions
See Step
Make an Equation
Single most important part of the process
Annual Revenue for GMAIL in the US
[# of gmail users in the US] X [annual clicks per user] X [average revenue per click]
[Google US revenue] X [% revenue from ads] X [% ad revenue from embedded (non-search) ads] X [% embedded ad revenue from Gmail]
Think About Edge Cases and Alternate Sources
What are the problems with your approach?
State limitations of your approach
Break it Down
Find a way to solve each component of the equation.
Construct a sub-equation
Keep it separate from larger equation
Review & State Your Assumptions
PICK NICE ROUND NUMBERS FOR CALCULATIONS
Update list of assumptions from step 2
State your assumptions to the interviewer
Explain WHY you’re making your assumptions
Do the Math
Take your time, do the math right.
Sanity Check
Give your answer to the interviewer BUT...
Make sure to double-check your work right after that.
If there’s an issue, it’s probably in the following areas
Original equation
Assumptions made
Arithmetic
Tips and Tricks
Round Numbers
Rule of 72
How long until something has doubled?
Divide 72 by the % increase
Orders of Magnitude
digits(a) + digits(b) =digits(a * b)
or
digits(a) + digits(b) = digits(a * b) + 1
Label Your Units
Keep track of your units and don’t screw things up
Consider Your Sources
If you’re thinking about sales, for example, consider all the sources:
Direct to Consumer
Vending Machines
Distributors
etc.
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