A living wage is also strongly dependent upon family makeup.  Two childless individuals can survive on far less per adult than a single parent with three children.<p>So for starters, do the BI scale per individual, and if so, how?  Assuming it scales flatly, it gives an incentives to have children because of economies of scale (this is not to say people will have dozens of children, as this is a single incentive among many, many of which are incentives to not have children).