Why wouldn't surveys, educated guestimates, etc. of the cannabis community include asking and/or reporting about growing for and purchasing from the for profit/black market, including how many home growers (legal or not) divert some significant portion of their harvest to illegal sales to 3rd parties? Besides being of broad interest, this is mission-critical data for legalization and law enforcement programs.
The "black market" is what the States (particularly if collecting taxes on dispensary sales), the dispensary industry, those politically involved in this issue on all sides, law enforcement, the concerned public (including cannabis users), etc. all want to know about. A prime rationale for legalization and law enforcement by States is the goal of destroying the black market. The success (or not) of gov't programs is something they (and ideally also independent 3rd parties) need to track to justify their budgets, convoluted legal sales regulations and black market-targeted law enforcement efforts.
