Product 101

Dec 1

/

4 min read

Prabhjeet Singh Arora

Guesstimates are one of the most commonly asked questions in product management interviews. They allow the interviewers to test the candidate's structured thought process, problem solving skills, quantitative ability, and an ability to arrive at reasonable assumptions. Guesstimates in product management interviews are very similar to those asked in consulting interviews, but they are more oriented towards technology.

In this blogpost, we look at the approach to a guesstimate question in a product management interview.

Now, any guesstimate question broadly involves 4 steps:

Step 1: Ask clarification questions

Step 2: Think aloud your approach (converse with the Interviewer)

Step 3: Work out your calculations

Step 4: Sense-check your results and summarise.

To understand these better, let us take a question and try solving it using the above mentioned approach. Consider the question - "How many pubG players are there in India?"

Asking follow-up questions is important to make sure that both the interviewee and the interviewer are on the same page. This also shows the interviewer that the interviewee is comfortable spending time in the problem space (which is a very important PM trait) rather than jumping right into the solution.

Here are some potential questions that immediately come to mind for this question:

• Are we talking about the pre-ban stage? Or do we want to calculate the number of users after the app's relaunch in India?

• Are we considering only mobile or only desktop or both?

• Who do we consider as an app user? Is it DAU (Daily Active Users), WAU (Weekly Active Users), MAU (Monthly active users) or any other criterion?

Let us assume that we are talking about the pre-ban stage. We are considering only mobile phone users. And let's also consider users who play pubG for 1+ hour every week qualifying as a PubG user.

At this stage, it is important to lay down the method we'll be using to approach the question. Let us take a top-down approach to solve this guesstimate, where we'll start with the population of India and then keep adding filters until we reach the WAU for PubG.

We can use the following approach to arrive at the WAU:

• Divide the population of India into different age groups.

• For each age group, Assume A= %age of population with smartphone access, B = %age of A with internet access, C= %age of B that plays games, D = %age of C that plays action-adventure games, E= %age of D that plays PubG weekly

• Then we add the 'E' for all the age groups to come to the required number.

Note: %age of population with smartphone access is different from %age of population that owns smartphones. Kids in their early teens may not own smartphones, but a large number of them would have access to smartphones of their parents.

Now that we have our approach worked out, it is time to do the actual calculations. At this stage, one would need various data points to solve the question. In most cases your interviewer will ask you to make your own assumptions to get to the final number. But in some other cases they might share data with you. Also, it is a good idea to round off the calculations to make them easier to solve.

For our question, let us assume that the population of India is 130 crores. We shall divide it into 6 age groups:

• 0-15 years: 30% of the population

• 16-25 years: 20% of the population

• 26-35 years: 15% of the population

• 35-45 years: 15% of the population

• 45-55 years: 10% of the population

• 55+years: 10% of the population

For 0-15 years of age group: Percentage of the population with smartphone access (A) can be assumed to be 40%. Percentage of A with internet access (B) can be taken as 80% as most people with smartphones will have internet access.

Percentage of B that plays games (C) can be taken as 50% as most children would start playing games on smartphones only after they have crossed a certain age.

Percentage of C that plays action-adventure games (D) is assumed to be 30%. And since PubG is a pretty popular action-adventure game, we assume that 80% of those who play action-adventure game, would play pubG for 1+ hour every week.

Now solving for this age group: WAU for PubG in 0-15 age group = (130 crores) X (%age of population in 0-15 age group) * (A) * (B) * (C) * (D) * (E) = 130 crores * 30% * 40% * 80% *50% * 30% * 80% = 1.49 crores.

Hence, there are approximately 1.5 crore users of pubG in the 0-15 age group. We perform similar calculations for other age groups as mentioned in the table below:

So the total number of weekly active users for PubG users is approximately 6.5 crores.

Note: It is a good idea to have certain common numbers in handy before the interview. For example, age distribution, smartphone penetration, internet penetration are very commonly used across the guesstimate questions.

**4. Sense-check the results **

At this point, we check if the intermediate or the final results make sense. If the numbers do not look reasonable, we might want to rethink the assumptions or approach. Results show that approximately 5% of India's population plays PubG weekly. This sounds reasonable. Also, the maximum number of players are in the 16-25 age group which again makes sense.

Product 101

Dec 1

/

4 min read

Prabhjeet Singh Arora

Guesstimates are one of the most commonly asked questions in product management interviews. They allow the interviewers to test the candidate's structured thought process, problem solving skills, quantitative ability, and an ability to arrive at reasonable assumptions. Guesstimates in product management interviews are very similar to those asked in consulting interviews, but they are more oriented towards technology.

In this blogpost, we look at the approach to a guesstimate question in a product management interview.

Now, any guesstimate question broadly involves 4 steps:

Step 1: Ask clarification questions

Step 2: Think aloud your approach (converse with the Interviewer)

Step 3: Work out your calculations

Step 4: Sense-check your results and summarise.

To understand these better, let us take a question and try solving it using the above mentioned approach. Consider the question - "How many pubG players are there in India?"

Asking follow-up questions is important to make sure that both the interviewee and the interviewer are on the same page. This also shows the interviewer that the interviewee is comfortable spending time in the problem space (which is a very important PM trait) rather than jumping right into the solution.

Here are some potential questions that immediately come to mind for this question:

• Are we talking about the pre-ban stage? Or do we want to calculate the number of users after the app's relaunch in India?

• Are we considering only mobile or only desktop or both?

• Who do we consider as an app user? Is it DAU (Daily Active Users), WAU (Weekly Active Users), MAU (Monthly active users) or any other criterion?

Let us assume that we are talking about the pre-ban stage. We are considering only mobile phone users. And let's also consider users who play pubG for 1+ hour every week qualifying as a PubG user.

At this stage, it is important to lay down the method we'll be using to approach the question. Let us take a top-down approach to solve this guesstimate, where we'll start with the population of India and then keep adding filters until we reach the WAU for PubG.

We can use the following approach to arrive at the WAU:

• Divide the population of India into different age groups.

• For each age group, Assume A= %age of population with smartphone access, B = %age of A with internet access, C= %age of B that plays games, D = %age of C that plays action-adventure games, E= %age of D that plays PubG weekly

• Then we add the 'E' for all the age groups to come to the required number.

Note: %age of population with smartphone access is different from %age of population that owns smartphones. Kids in their early teens may not own smartphones, but a large number of them would have access to smartphones of their parents.

Now that we have our approach worked out, it is time to do the actual calculations. At this stage, one would need various data points to solve the question. In most cases your interviewer will ask you to make your own assumptions to get to the final number. But in some other cases they might share data with you. Also, it is a good idea to round off the calculations to make them easier to solve.

For our question, let us assume that the population of India is 130 crores. We shall divide it into 6 age groups:

• 0-15 years: 30% of the population

• 16-25 years: 20% of the population

• 26-35 years: 15% of the population

• 35-45 years: 15% of the population

• 45-55 years: 10% of the population

• 55+years: 10% of the population

For 0-15 years of age group: Percentage of the population with smartphone access (A) can be assumed to be 40%. Percentage of A with internet access (B) can be taken as 80% as most people with smartphones will have internet access.

Percentage of B that plays games (C) can be taken as 50% as most children would start playing games on smartphones only after they have crossed a certain age.

Percentage of C that plays action-adventure games (D) is assumed to be 30%. And since PubG is a pretty popular action-adventure game, we assume that 80% of those who play action-adventure game, would play pubG for 1+ hour every week.

Now solving for this age group: WAU for PubG in 0-15 age group = (130 crores) X (%age of population in 0-15 age group) * (A) * (B) * (C) * (D) * (E) = 130 crores * 30% * 40% * 80% *50% * 30% * 80% = 1.49 crores.

Hence, there are approximately 1.5 crore users of pubG in the 0-15 age group. We perform similar calculations for other age groups as mentioned in the table below:

So the total number of weekly active users for PubG users is approximately 6.5 crores.

Note: It is a good idea to have certain common numbers in handy before the interview. For example, age distribution, smartphone penetration, internet penetration are very commonly used across the guesstimate questions.

**4. Sense-check the results **

At this point, we check if the intermediate or the final results make sense. If the numbers do not look reasonable, we might want to rethink the assumptions or approach. Results show that approximately 5% of India's population plays PubG weekly. This sounds reasonable. Also, the maximum number of players are in the 16-25 age group which again makes sense.