We conducted a randomized controlled trial of short-term management training for small manufacturers in two study sites in Vietnam and collected follow-up data repeatedly for two years to assess longer-term impacts than the existing studies of management training. Our training programs introduced participants to Kaizen, a common-sense approach to production management. In both sites, many participants started to recognize the importance of learning about management and improved their management skills. The impacts on management skills were statistically significant two years after the programs. Our results suggest that the training program increased participants' value added in one of the two study sites, likely because they learned how to eliminate wastes in production. (C) 2015 Published by Elsevier B.V.