An engineer suggests showing suggested Buy/Sell Groups on users' newsfeed instead of the People You May Know section. How do you determine if that is a good idea or not?

Context

First let's establish a common understanding of what the FB Newsfeed is and how users use it. The FB Newsfeed is the first thing users see on the homepage of Facebook. It is a continuous stream of the most relevant content in the form of posts from around the platform. 

To further frame this, Facebook's mission statement is to bring the world closer together and give people the power to build community. The Newsfeed helps further this mssion by giving making it easier for users to discover and consume content from around their community.

Goals

As mentioned above the Newsfeed is the first thing users see when they log in and its there for a reason. The goal of the Newsfeed is to serve as one of the primary ways users to consume and engage with content on the platform. In order to monitor the success of the Newsfeed overall we could monitor the average amount of time spent on the Newsfeeder per user. Secondarily, we could examine the average number of posts viewed and the average number of interactions with posts per Newsfeed session.

Now that we have a better understanding of what purpose the Newsfeed serves, let's look at the individual goal of the two different options we are debating:

• Buy / Sell Groups -> Help users buy and sell goods directly with members of their local community
• People You May Know -> Help users connect with others and expand their network

• Pros
  • More group members, more potential buyers & sellers, more engagement within the group
  • Potential for new connections online and IRL
  • Users more likely to explore FB marketplace as wel
• Cons
  • Safety concerns of strangers meeting in person
  • People aren't always looking to shop or purchase second hand
  • Buy / Sell group suggestions may not be what the users interested in

• Average session length
• Average amount of time spent on the Newsfeed
• PYMK:
  • Average number of suggested profile clicks
  • Average number of friend requests sent
  • Average number of friend requests accepted
• Buy / Sell Groups:
  • Average number of group clicks aka views
  • Average number of groups joined
  • Average number of messages sent by users in the newly joined group

• # of Friends: If the user already has 1,000+ friends on the platform they probably have a strong enough network already and PYMK may not be as of much value, conversely users with a small number of friends would find more value in it
• Strength of the Friend Suggestions: Whether or not suggestion is very likely someone the user knows
• Activity Levels of the PYMK: If the people we are suggesting aren't very active on Facebook then there will be less opportunity for mutual interaction and engagement down the line
• Affinity between the User & the Buy / Sell Group: If the user isn't interested in the goods being sold or is no longer living near that area they aren't going to join, conversely they may be really into say Pokemon Trading Cards and join right away
• Activity Level of the Buy / Sell Group: If the group doesn't have a lot of members or activity then the user isn't going to be inclined to join and won't get as much value out of it if they do join
• Penchance for using FB to Buy or Sell goods: If the user has been active in other Buy / Sell Groups or used FB Marketplace before then suggesting Buy / Sell Groups to them would probably be a value add

Hoping this helps you answer this Facebook execution PM interview question.

Clarification:

1. Are we talking of Facebook Mobile app or web version? Assume App

2. Do we know the basic reason behind engineer's suggestion ? Assume better disoverability for users for buy/sell group leading to driving engagment via news feed funnel

3. Do we want this to rollout to a specific geography vs global?Assume Global

FB mission is to connect people around the world by providing them tools and features to do so. Buy/Sell group actually connects not only intentional buyers/sellers but also who could benefit from window shopping and increase connections within the users in the buy/sell group sharing same passion and interest.  

The engineer's proposed new idea needs a tradeoff conversation with us going through 

1.pros and cons of it, 

2.defining hypothesis , 

3.identify metrics to back our hypothesis validation ,

4. define A/B test and run it for a specific traffic and based on outcome, 

5. finally giving recommendation of a go, no-go for this change

Current User Journey>> User logs in to Fb app>>>>Lands on NewsFeed Page> Click PYMK tab>> Scroll and finds Buy/Sell groups

New User Journey>> User logs in to Fb app>>Lands on NewsFeed Page>>croll and finds Buy/Sell groups

Based on the Pros-Cons analysis, we can define our hypothesis to test whether we are heloing our users as well as moving the key metrics in right direction or not. Our hypothesis is that moving Buy/Sell groups to newsfeed section should drive more engagement from the users on Newsfeed as well as more adoption for Buy/Sell group.

Metrics to measure:

1. DAU/MAU( Users coming to Newsfeed app and viewing atleast 1 feed) : Atleast remain intact or may increase 

2. Adoption Rate (Average # of DAU/MAU users joining new Buy/Sell groups) : Should Increase 

3. Average # of interactions(likes, shares, comments) per user via buy/sell group.

4. Churn Rate( Drop off rate of users who dont feel motivated when shown buy/sell group in newsfeed and closes the app OR use directs to another Fb feature): Should be intact 

We will run A/B testing to validate our hypothesis. Since engagment is more precise and significant when we have it calculated over a month, so I would propose to run this experiment between 5-6 weeks. I would also like us to test it via 2 similar set of unbiased traffic - 1 for Control(buy/sell group in PYMK) and other for variant(buy/sell group in Newsfeed). 

Based on data, I am assuming we dont see surge in engagment from users with the case and so we will not proceed with the change.