The International Growth Centre features a blog post by Stephen Anderson-Macdonald, on his IPA study with Bilal Zia and Rajesh Chandy, looking at the mixed history of research on business training for micro-entreprenurs in developing countries and asking if all business training is the same?  They separated out finance from marketing trianing, and compared each to a control group, finding that they both worked, but seem to work by different routes, and differently for different people. Read a summary of the project here.