Your response isn't indicative of very well-thought-out input. Do you mean OP's criteria for participants aren't specific enough? It's conceivable the invitation is designed to be on the loose, informal and imprecise side, which might sound academically unfocused, but I wouldn't be surprised if OP's description is set wide to get as "random" a sample of FT contributors as possible. Maybe. Then again, OP could definitely be more detailed. But suggesting so doesn't mean the project isn't thought out.