How many reviews are left on Amazon on a given Monday?

I know Amazon's revenue for 2019 was roughly 300 Billion and 5% of that came from Amazon Prime but that is world wide. So I'll choose 2% from Prime, Which equates to 6B. Now let's devide 6B by 120 (Prime subscription) which gives 50Mil.

So out of 80 Mil that have used amazon.com, 50 Mil are Prime users and I would tag them as high usage (buys multiple times a week) and I would put 20 Mil as Bi weekly shoppes and 10mil as low usage (once a month)

Out of 50 Mil, I would say only 10% of the people write reviews and probably around the same for biweekly and I would not touch monthly or low usage as it would be negligible (Low engagement anyways).

Rationale for 10% : Most of the reviews are if the users are very happy or very unhappy about a product and Amazon does a good job of vetting products that are really crappy.

So that puts us at 10% of 50 Mil = 5 Mil and 10% of 20 Mil = 2 Mil and a total of avg 7 Mil reviews a week

Now, I know for the fact (I have read it somewhere) that majority of the delivery happens on Wednesday and Majority of the Orders happens on Thursday / Friday (Excluding any holidays / deals where there is a spike through out the week)

Given the above information, I would say 60% of the reviews are written on Wed / Thursday => 60% of 7 Mil = 4.2 Mil
I would then allocate 10% each of reviews are written on Friday, Sat and Tuesday => 700k each = 2.1 Mil and
5% on Sunday and 5% on Monday which equates to 350k each since there are very less deliveries on Sunday and Monday being a working day (busy) after weekend, I would keep it at 5%.

So the summary is, there is roughly 350k reviews left on any given Monday on Amazon.com within in the US

Self Critique: The highest number of ratings I have seen is 2000 reviews for a product and least is couple hunderds. The patterns I have seen is that less than 25$ item gets a ton of ratings and as the price increases the number of reviews decreases. Perhaps we could split the 10% rating for weekly and bi weekly based on average product price and then do the math.

PM Team · Answer 2 · 2020-08-03T22:02:40+0000

We need one clarification in the question about the country in which the question is applicable to. As Amazon is present in most of the countries around the world, is the question applicable to all the countries put together or any specific country like India or US

Let's assume that the question is about Amazon India.

90% of the time reviews will be given by people who have purchased that item through Amazon recently. 10% could be by people who have already purchased it outside and wanted to share their experience.

So, we I derive the average number of reviews on a day from the average number of orders and the % of users who purchase and give reviews to products using the below formula:

# of reviews per day = # of orders per day* % of users who give reviews

# of orders per day = ((# of users who shop online in india * average # of orders per year ) * Amazon India's market share)÷365

In india about 1/3rd of the population is shopping online which is about 400 million

From avid shoppers who shop weekly to people who shop rarely, it would be safe to assume that a user shops twice in a year online. That would make it 800million orders. Amazon India market share is about 30% . So the number of Amazon orders = 240 million.

# of orders per day = 240 million÷ 365 = ~ 750k

Usually about 10% users come back and write a review of a product that they purchased.

# of users who give review per day= 10% of 750k = 75k

Usually people have more time during weekends and tend to right more reviews than average and Monday being the week's starting day, may see less traffic than weekends. If we assume Mondays receive only 80% of the average activity, the average number of reviews on a Monday could be equal to 60k

Bishnu p · Answer 3 · 2020-11-04T20:54:18+0000

So the question is ‘How many reviews are left on Amazon on a given Monday?’

Step-1 : Clarifying the scope of Question:

Are we looking at a specific region like US, India? Say we need to focus on US.

Amazon has many product lines like Amazon Fresh, Amazon music, Amazon e-Book e-commerce etc. Are we looking at a specific line of business ?

Lets assume the interviewer says you can narrow down the scope as per your consideration. In that case, let us focus on Amazon.com and no specific business line.

There are many other e-commerce sites that Amazon owns like shopbop, zappos, and Woot. Are we also considering those additional sites?

Say we will focus on the Amazon.com for now.

Lets take a moment to think about the calculation and list down the equation.

Step -2 : Main Equation

To be able to calculate the number of reviews on a Monday, we will need to calculate the number of orders received on a day multiplied by the percent of buyers who share a review on the site about their experience with the whole buying process or about the product feature that they bought.

#Number of Reviews = Total number of Orders online * percent of shoppers giving a review online

Step – 3 : Let us dive in further Break down each component.

#Total number of Orders online = # of users who shop online in US * percent of Amazon’s market share in US

ð #of users who shop online in US = 70% of US population

ð Market share of Amazon in e-commerce in the US = 50%

Step-4 – Calculations and Assumptions

ð Assuming US population is close to 300 million, the equation comes to

ð 350 million * 70% * 50% = ~120 million

Facts say around 25% of US online shoppers have shopped at least once a month. Assuming there would be frequent shoppers as well as casual shoppers who have shopped online once a while, it is safe to assume there can be 3 shopping orders per person every year.

So #Total number of orders online = 120 * 3 = 360 million

#Total number of orders online per day = 360 million/365 = ~1000 k

Assuming there will be 10-20% of users who will leave a review,

#Total Number of Reviews = 1000k* 20% = 200k per day .

Assuming Monday is a busy work day, people usually would have provided their reviews on weekend. So there will be considerably less reviews on Monday.

#Total number of Reviews on Monday = 5% of total orders received = 1000k * 5% = 50k

Step-5 checks and revisit edge cases if any– We are not considering the Prime users who usually shop multiple orders in every week. We assume Monday is a working day for most folks. What about the return reviews as some of hot products like clothes will be tried and verified on Monday? That can add up or compensate the review rate to some extent say by another 10% . So the reviews could be around 55-60 k on a normal Monday at Amazon.com shopping site in the US.

Prabhav Gupta · Answer 4 · 2020-08-05T04:56:11+0000

Clarification questions -

Any specific region that we are looking at? Say US only
Any specific channel? Say mobile and desktop
Any specific time frame? Say one year

Assumptions -

Reviews on Monday will be on orders done during the weekends
Majority reviews are given by people who have ordered a product from Amazon
Products are delivered in 1-2 days
Rating is given before review in the product flow

Approach -

Amazon.com has a logged in user base of 1 million, of which say 5 lakh place orders
Each user places, on an average, 5 orders
Total orders in an year - 25 lakh
Assuming majority (60%) orders are placed over the weekends, as that is when people have time
Total orders placed over the weekends - 15 lakh
Assuming each order will not get a review -
1. Split of type of users who order - Motivated (20%), Demotivated (60%), Dissatisfied (20%)
2. From the above lot, only the "Motivated" and "Dissatisfied" will be eager to give rating
3. Only 10% of the users who give rating actually write a review
Total ratings (on all Mondays) - 40% X 15 lakh = 6 lakhs
Total reviews (on all Mondays) - 60K
Total reviews on any given Monday - 60000/ 52 = 1153