Question: Explain why a team starting a brand-new machine-learning application should define a dev set, test set, and evaluation metric quickly, and why the same rush is less important for a mature application.

Sample answer: A new project benefits from a fast evaluation setup because the team needs a shared way to judge ideas as soon as possible. With a clear metric and split data, people can compare approaches consistently instead of debating different success criteria or spending too long on setup details. It is usually better to begin with a simple, workable evaluation plan than to delay progress while trying to make the first version perfect.

For a mature application, the situation is different. The team already has a functioning system and an established direction, so it can afford to spend more time refining the evaluation data and metric. That extra effort can improve measurement quality, but it is less urgent because the team is not trying to define the project from scratch.

Key points:

• A quick evaluation setup gives the team a shared target
• Early progress matters more than perfection on a new project
• A simple metric and split can prevent wasted effort
• Mature applications already have a working direction
• Mature teams can spend longer improving evaluation quality

Rubric: Full credit answers both parts: why speed helps a new project, and why a mature project can take longer. Partial credit is appropriate if only one of those ideas is explained.