Case Interview- Root Cause Analysis- Why does a grocery e-commerce app have 25% lesser sale?
This is blog#3 in the series of blogs of case interviews. Let us do a root cause analysis case interview.
Interviewer- A grocery e-commerce app has had 25% lesser sale. Why?
Initial Clarifying Questions
Candidate- Thank you for the question. I have a few clarifying questions. Is this for the Indian market?
Interviewer- Yes, you can assume the market is the Indian market.
Candidate- Since when are you seeing this problem?
Interviewer- From last week.
Candidate- Can I take a few minutes to gather my thoughts?
In the interview so far, the candidate has not jumped to the solution directly. The candidate asked initial clarifying questions. The candidate asked for time to put some thoughts together which is a great practice in a case interview.
Typical answers from candidates are lesser cart additions could be because of different reasons depending on what the root cause is. Then they go on and list all the probable root causes without asking clarifying questions.
The interviewer wants one or two main root causes for the problem. The question is generic, but the expectation is for you to analyze the problem, ask relevant questions, and come to the probable root cause. The interviewer is not looking for an instant answer like traditional interviews. This is not a test of one’s knowledge and facts. It is a test of one’s ability to deal with a situation with lots of unknowns.
Let's go ahead and see how the candidate approaches this.
External Factors
Candidate- For this problem, there could be external reasons or internal reasons. Let me start by asking questions related to external factors.
Interviewer- Go ahead, please.
Candidate- Did a new competitor enter the market in the last week or so?
Interviewer- No major new entrants in the market that we know of.
Candidate- Was there a sale/major discount offered by any of the existing customers in the last week? This is like what Flipkart does in a “big billion-day” sale or Amazon does in a “Great Indian Sale”
Interviewer- No sales or offers during the last week by competitors.
Candidate- Any factors that affected the overall sale of groceries last week? Was there anything major that affected the entire grocery supply chain? For example, a strike by truck drivers/ last mile delivery drivers.
Interview- None.
Candidate- Was this 25% reduction in cart additions observed in a particular geography or demography or segment or type of products?
Interview- We have not seen a particular pattern.
Candidate- Are there any other external factors that I might have missed? Or can I assume external factors did not impact the problem?
Interview- For now, please proceed with analyzing internal factors. We can come back to the external factors if required.
The candidate has asked many questions related to external factors. There could be more. However, the candidate has enough clarity that major external factors may not be the reason for the problem the grocery e-commerce company sees. Also, the candidate got the blessing of the interviewer to go ahead with the internal factor analysis. So, let's see what the candidate does from now on.
Internal Factors
Candidate- There might be a tool that collects data on cart additions and other data that the company uses. Was there an issue with the data-collecting tool?
Interviewer- The data we have been receiving has been accurate. The tool is fine.
Candidate- Are you seeing this in the mobile app, web app, or both?
Interviewer- We see this problem just in the mobile app.
Candidate- Was there an increase in uninstallations in the Android app last week?
Interviewer- Nothing alarming.
Candidate- Was there an app update that was released in the last week?
Interviewer- Yes we did have an app update last week.
Candidate- Was this update in Android or IOS or both?
Interviewer- This app update was only on the Android app.
Alright, now we know what the problem is because of the app update on the Android app. Do we know the final root cause though? Do you stop asking questions here? It is not a good practice to jump to conclusions without asking further questions. It may or may not have been because of the app update. The app update might have been a mere coincidence. If it is indeed because of the app update, which features in the app is causing this problem? This is something that we need to find. Let's proceed.
Candidate- Did the update have anything to do with cart additions?
Interviewer- We changed a few things in the user flow. Do you have a more specific question?
Candidate- There is a famous case study of the 300 Million Dollar button. An e-commerce company added the REGISTER button after the add to cart. They saw a significant drop in sales when they did that. When they interviewed people, the customers said, “I am here just to buy some products. I don't want to share my personal information.” That's when the CONTINUE AS GUEST button was invented. Here the company added the continue button, instead of the register button. Their sales jumped by 300 Million Dollars. That's why the button was called the 300 Million Dollar button.
Did the e-commerce company here introduce the register button after the add to cart?
Interviewer- No. There is no register button after the add to cart.
Here the candidate tells a little story showing off the knowledge of a famous case study. At the same time, the candidate has asked a clarifying question. This will leave a good impression on the interviewer.
Candidate- Did the update have anything to do with the add-to-cart button? Is the add-to-cart button working?
Interviewer- We have not seen a problem with the add-to-cart button. It works fine. Products get added to the cart.
Candidate- When a user clicks on the cart button, does he/she see the products added? Does the cart button work fine?
Interviewer- Yes the user does see the products in his/her cart. No problems with the CART button.
Candidate- Are there bug reports related to the user being able to make payments and checkout?
Interviewer- We did see some bug reports when a user tries to make a payment.
BINGO. Now we are very close to the root cause. Time to go for the kill. Here one must not stop and conclude. Ask a few more questions to get more clarity.
Candidate- Is there a problem with paying digitally with a credit card, debit card, Wallet, UPI, etc.?
Interviewer- No. we don't see a problem with any of the payment methods above.
Candidate- Is this related to the CASH ON DELIVERY option?
Interviewer- Yes, we did see bugs related to cash on delivery.
Candidate- I think that the 25% lesser sale in the e-commerce grocery app is related to the cash-on-delivery button in the payment section of the Android mobile app.
CONCLUSION
In a root cause analysis case interview, one needs a framework to approach a problem. A framework helps in giving a structure to the problem.
There are many frameworks. 5 why analysis (asking why 5 times will get to your root cause). However, this framework does not show one’s ability to analyze things in detail in a case interview.
The framework I prefer in a case interview is external & internal factor analysis. Analyzing the external factors and internal factors helps to get to the root cause.
PS,
Please see the links to all my case interview blogs below.
Blog# 1- Case Interviews#1- Introduction- Click Here
Blog#2- Case Interviews#2- Guesstimate- Click Here
Blog#3- Case Interview#3- Root Cause Analysis- Click Here
Blog#4- Case Interview#4- Market Entry- Click Here
Blog#5- Case Interview#5- Product Design- Click Here
Blog#6- Case Interview#6- Profitability- Click Here
Blog#7- Case Interview#7- Product Metrics- Click Here
