Understand the bell curve for product growth.
Whether the product is in initial, growth, saturation, stagnation(decline) phase in that country.
Assumption #1: Assuming the product is in growth phase.
Analyse whether the user is signing up for facebook or for using some other applicatons (using sign up with facebook).
Assumption #2: Assuming the user is using facebook app.
Analyse which of the user engagement metrics is declining : fb chat, fb groups, fb pages, user posts or quiz/fb apps based posts.
Analyse the last activity that the user spends time upon before leaving the page.
Solving the problem:
- If the fb posts feature is getting less engaging: Engage the users more by showing the posts by dividing into several groups and applying A/B tests: Posts by direct friends, posts by mutual friends, trending posts etc.
- If fb pages or fb groups are getting less engaging: Encourage more group posts in the main feed of the users who're the top commentors/ medium commentors/ less commentors.
- If quiz/ fb-app posts are less engaging : Suggest(Incentivise) the app developers to create more new /innovative/ trending apps.
Measuring the Success:
Analyse the results of the hypothesis over a month and apply the appropriate changes over the next months and observe the user engagement/ the rate of users coming back within 30 days.