Studies have shown mixed results whether there is a positive relationship between small businesses’ management accounting information and their success. In uncertain situations decision-makers tend to rely on their visions and experiences rather than on formal decision-making models. Entrepreneurship is based on uncertainty and innovation, and may therefore be inhibited by management accounting aiming at reducing uncertainty. Small businesses are partly entrepreneurs, partly ‘livelihood businesses’. The question in this paper is: Are there systems of management accounting in small businesses that are less or more effective in different situations? In a cluster analysis of 124 small businesses we found four relevant systems of management accounting regarding line of business. Moreover, there were significant differences in the market effectiveness when the uncertainty of the situation increased. Finally, the difference between the four systems was significant in the combination of strategic behaviour/pay to board/MD.