Most businesses delay engaging a research partner because they think they'll need to brief perfectly first. They won't, and you don't.
A good consultant will help you sharpen the question itself. Half the value of an external research partner is forcing you to articulate what you actually want to know — and what you'd do differently if you knew it.
Before commissioning anything, ask: what decision is this research informing, what's the threshold of evidence that would change our mind, and who owns the outcome?