It does seem a bit too convenient that they are reporting on and reporting the researcher conclusions without feeling the need to actually publish the underlying research and opening themselves to scrutiny - but hopefully that will come out soon enough.

The difficulty of doing this in the field is trying to figure out what the appropriate methodologies to use are. It's not like it's easy to collect this information over time and ensure people are forthcoming (and in many regions where microfinance thrives, the poor are especially and legitimately suspicious of authority and people wanting personal information). Collecting information often becomes a messy process in collecting objective and comprehensive data.