Practice Set: Launch and Mixed Cases

A prompt that says a new feature has early adoption but rising support contacts does not announce whether it tests metrics, diagnosis, launch judgment, or growth reasoning. The first error is proposing tactics before deciding what decision the prompt requires. A case shape is the reasoning structure that matches the decision, such as a metric tree for success measurement, a validity-first diagnosis for a drop, a rollout plan for a launch, or bottleneck analysis for growth.

This practice set contains six unlabeled cases. Each mixes launch, build, or growth signals with partial information. Cases 1–5 each have two hints and a full answer; Case 6 has two hints and is answered in the deep dive that follows it. A table of case shapes and a short quiz close the set. Any figures in the prompts are assumptions, not observed business data. We begin every case by clarifying the population, time window, and decision, then state a success definition before offering an intervention.

Problem 1: Template starts rise

Scenario: A team proposes a shortcut that lets eligible new users create a project from a template. In the first week, template starts increase. Should the team expand the feature?

Question: What should we use as the success measure, and should the team expand the template shortcut?

Solution

Choose a launch structure rather than treating template starts as success. Ask whether the goal is more projects, faster time to a first useful project, or durable use after creation. Define the primary metric as the share of eligible new users who create and return to a project within the agreed window. Pair it with guardrails such as template error rate, support contacts per exposed user, and projects deleted soon after creation.

Recommend a staged expansion only if exposure is recorded correctly and the primary metric improves without guardrail harm, checked against the intended comparison group and split by desktop and mobile. If templates reduce setup friction, time to first project should fall among exposed eligible users. If starts rise but return use does not, the feature is generating low-value projects rather than activation.

Problem 2: Engagement falls after a rollout

Scenario: Two days after a feed-ranking change reaches all users, daily active users fall. Notifications sent per active user also fall. What should happen next?

Question: What should happen next, and how ...