Two fundamental aspects of decision-making concern stability and capability: is the process stable and predictable and does it meet the requirements? These aspects are often studied by use of control charts and of capability studies. The former comprises techniques based on plotting the longitudinal outcome of some process measure and estimation of what could be called the “natural variation” for the process. Capability studies are based on comparisons between the variation and tolerance limits.If these aspects are addressed explicitly at all, then they often seem to be dealt with incompletely or even inappropriately. Control charts are often described as techniques for determining when the process should be adjusted. This is evidently one possible use for control charts, but it is far too restricted. We claim that control charts have their most important use as tools for discerning what kinds of actions which might be appropriate in improvement efforts, hence an instrument to be used in fairly high level decision making. As for capability studies, these are often made without considerations to the process stability. This can result in making the final capability indices more or less useless.The intention in this paper is to advocate an alternative and more general perspective on these two aspects. The basic argument is that the tools should first of all be used on the level of manager's decision-making. A simple model for the use of the tools is proposed. The model could hopefully provide support to decision-making as it results in better facts.