The purpose of this paper, which participates in the lively debate between the Learning School and the Planning School, is to investigate whether a business plan can still support planning a start-up in uncertainty conditions. By analyzing the strengths, weaknesses, opportunities, and threats of the business plan process, we propose an evolution of such a process, through the use of simulation models, to manage uncertainty. Using simulation models, especially what-if simulations, the start-up founder is able to improve the cognitive process in order to assess the pro-ject’s feasibility. Furthermore, with simulation, business plan overcomes some of its traditional weaknesses and improves its strengths and opportunities. It can also become a training tool in the entrepreneurship programs promoted by public insti-tutions. By integrating forecasting, planning and simulation models, the business plan can be more comprehensive and provides more information about the envi-ronment in which the start-up has to play the game. Thus, the business plan be-comes "not just an evaluation of a project’s profitability, but also the future story of an idea, in which people are the central point of the success".
Keywords: Business plan, uncertainty, simulation models, decision making, start-ups