Social audits flawed as a way of driving sustainable change

Thought provoking piece on The Guardian from an Oxfam manager about social audits as means to drive change in supply chains:

"The ethical audit industry is estimated to be worth $80 million dollars a year. The World Bank recently calculated that parallel, or duplicate, audits in the Vietnamese garment industry had added $50 to the cost of each worker per year. In terms of "lean manufacturing", audits could be seen as a form of waste, adding cost but not real value."

Funny how social/ethical audits do not seem to work for NGOs but somehow they will be great in procurement as I have seen mentioned time and time again at conferences? 

As I argued in my paper about the growth of external compliance in procurement (of which sustainable procurement is a key example), it is important to follow the money and the interests behind such proposals. I am yet to see their proponents having an honest debate about the costs and downsides of their proposals.