Spoke with a recruiter who contacted me about a role there a while back. After an exploratory interview that was a discussion of leading a research team, they requested that I complete a heavy statistical analysis of product mix using their own data set and issue a set of recommendations. It would have required 30 to 40 hours of hard-core data scientist-style analysis in Tableau and R.
I have a rule of never working for free, and the amount of work requested was downright exploitative. Secondly, it was a question set for a data scientist as an individual contributor, and not a strategic question set for a researcher.
I declined.