No expert by any means but in an estimation question is always good to end with a sanity check. In this case, the sanity check could be that according to Dominic Barton (McKinsey's global managing... (more)

# All questions tagged estimation - Consulting Q&A - PrepLounge.com

Ask a question## Number of Applications McKinsey Receives Per Year

## How to estimate the number of taxis in Köln ?

Hi, I would estimate this way. I hope it helps. - (N° of residents * % residents no driving license * % residents no car * % residents no public transport) * N° drive over year / AVG N° of passag... (more)

## Do you structure a market sizing question differently than other cases and how detailed do you get in segmenting ?

Hi Marilena, good question. I would always structure such a case completely top down. E.g. in your case, start with the population, then % of people needing glasses, % of those in reach of your... (more)

## How to estimate the market size of trucks in China?

What is pre-talk of MBB? Anyway, let's define market size of trucks as the number of trucks used in China domestically. [Pop China] * [% adult] * [% drivers license or drives illegally] * [% wit... (more)

## Calculation Airport Passengers in 1 year

Hi Franziska, I'd try the following: 1. The population served by a particular airport (if there are several airports in an area, also assume an airport's share) 2. Based on personal experienc... (more)

## Estimation: How many people going through the airport each year questions??

Couple of thoughts: General approach is fine! Don't overcomplicate estimation questions Just make sure you also think of non-passengers! You can segment e.g. into arriving passengers, departing pa... (more)

## How many cars across a local bridge (like Golden Bridge) a hour/day?

I'd look at the population surrounding the bridge, e.g. 2 cities from each side of the bridge then * % adult * % with drivers license * % with car * % travels to work * % travel to work through thi... (more)

## Estimation of # people ever lived on earth

Hi Mike, I would probably use a variation of the case "How many babies are born in the world per year", that is presented in one of the videos on this platform. a) # of people ever living = numb... (more)

## How many active internet website there is on internet?

Hi, thanks for your question. I think the case is essentially testing your ability to segment a massive concept like 'internet websites' to its components. Below is my answer for this case: Assume... (more)

## Estimate case type based on interviewer profile

Hi, 1) I would recommend you to prepare for case interviews as much as possible instead of trying to predict your case types. The much better indicator will be the specialization of the company its... (more)

Hi Thierry, You can improve in a simple and effective way your undestanding of proportions and checking final results through: 1) Use measure approximation 2) Prepare some benchmark measures in adv... (more)

First, understand what is the "ocean" (e.g. assess the main dimensions of plane, etc.) Second, understand the unit with which you deal (e.g. ball, ppl, table) Third, understand the limitations &... (more)

## Estimation Book

Hi, Several sources: Market-sizing and brainteaser books (e.g. Are you smart enough to work at Google?, How would you move mount Fuji?) MBA Casebooks - the most known - Columbia, MIT, Whart... (more)

## When is it OK to estimate? Is a fast estimate better than a slow but accurate answer?

Hi, Ask the interviewer 1-2 times to get a sense of how comfortable he is with rounding numbers and how many zeroes he requires. Continue with an assumption that you should keep that level of... (more)

## Market size of vans repairs

Hi, I would calculate it the following way: 1) Calculating the number of private vehicles Calculate the number of households in UK Multiply by the average number of cars per household... (more)

## Estimate the sales in volume of instant coffee in UK for the next 4 years

Hi Riccardo, I don't think that's a bad approach - is GDP change specifically provided? It is not what I would instinctively have gone for, but it does make sense. I agree with Angelo's point ab... (more)

## Total Number of Gas Station/Restaurant Question

my approach would be to match supply with demand. for the gas station case, on the demand side: -Start with the total population of the area you're looking into -get the number of households -then... (more)

## Moltiplications/divisions with 6+ digits numbers, estimation math_Tricks

Hi Anonymous, in general, the main issues with big numbers is forgetting zeros during operations. Potential tips to deal with big numbers are the following: Use correctly 10^ powers in your m... (more)

## Guesstimate: Population question

Hi, Assume how much time it takes the population to double (let's say 2 years as they need 2 kids). So the population will double 5 times in 10 years Population in 10 years = 2*2^5 Best

## Company Estimation and Analysis

Hi, Not sure if I understand your question correctly. For commercial DD you can use the following structure: Market Size Growth rates Profitability Segments Distribution channel... (more)