Developing countries are pressured to adopt administrative solutions that the international community considers best practice. Some claim that these practices do not fit such contexts. How could one assess the fit or relevance of a best practice? This article suggests a basic answer: Look at the degree of difference between the proposed adoption context and the context in which such practice emerged as ‘best’. This answer emerges from a discussion on the basis of the new institutional ideas about change and diffusion. An empirical analysis of public financial management reform in African countries suggests support for this answer: Good practices are most evident in countries least different to the developed nations where practices originated and least evident in countries most different to these developed nations. The article contributes to a literature on best practice and yields fundamental messages for development, including the point that best practices are limited as administrative solutions in many developing countries. Copyright © 2011 John Wiley & Sons, Ltd.