Ask a Seed VC: How can I answer market size questions about a nascent industry?

Welcome back to Ask a Seed VC, Eniac’s advice column about startup fundraising and investing. Today’s question comes from a founder who requested that they remain anonymous:

My startup has seen some very strong growth recently, having gone from $0/mo -> $50k/mo in revenue in the past 6 months but as we bring a new model (content licensing) to what is still a nascent industry (digital wellness) we often get questions around market sizing.

Although some investors just get it, I have struggled to consistently answer these questions due to a lack of data around the content side of digital wellness. I’d love some advice on how you feel this could be answered well?