You run growth at a B2C subscription app. On Tuesday 12th, new signups fell 22% day-on-day and have stayed at the lower level for six days.
What you know: traffic is flat. The signup page loads normally. Paid spend is unchanged. App store rating is unchanged at 4.3. A release shipped on the 11th containing a new onboarding screen, an analytics SDK upgrade, and a copy change on the pricing page. Support tickets are up 4%, all unrelated to signup.
Diagnose the fall. Say what you would check first and why, what each result would rule in or out, and what you believe the most likely cause is. Do not propose fixes until you have named the cause.
100 points, 60% to pass.
Separate 'fewer people tried' from 'fewer people succeeded' before anything else — traffic being flat already points at conversion, not acquisition. Then segment: platform, geography, funnel step. The release is the obvious suspect but contains three changes, and the analytics SDK upgrade is the trap: an instrumentation change can make signups appear to fall without any real drop. The strongest first check is whether a second, independent source (payments, database row count) shows the same fall.