Influencer ROI Dilemma

You've recently joined a fast-growing e-commerce marketplace for emerging fashion designers, as the Head of Growth. The platform has gained traction among millennials and Gen Z, with 500,000 monthly active users.

You want to launch an influencer marketing pilot to accelerate user acquisition and brand awareness. However, based on your experience, you know that influencer campaigns often require multiple iterations to achieve optimal ROI. You're concerned that using ROI as the primary metric for the initial collaborations might prematurely kill this potential growth channel.

→ How would you design the influencer marketing pilot program to allow for optimization and learning?
→ What would you propose as the north star metric for the short term, and why?
→ How would you communicate your approach to stakeholders who are focused on immediate ROI?

See hint