Under-researched topics

David Mckenzie reports this funding of under-researched topics according to: 

50 assistant professors in the U.S. and at international universities who do development research. 

At first sight, the results make sense. A lot of research is being done in the area of micro-finance. I wonder: if one separates the opinion of US based economists from those of international economists (especially those living in developing countries), does one find a different set of under-researched topics? 

Besides, It looks like the categories are not well defined. For example, conceptually, "poverty" overlaps with "micro-finance," which overlaps with "small and medium enterprises." 

The idea of listing under-researched topics is great, I just have some concerns with the definition of the categories above.