As important as all such characteristics are, perhaps the most fundamental distinguishing characteristic is something else-namely, the purpose and desired outcome of the use of the tool or model. Most broadly, forecasting tools and models are organized around two purposes. Exploratory tools seek “simply” to understand the path of a system, whereas normative tools identify a desired future and then assess the likelihood of attaining that future and/or identify means by which the path toward the

desired outcome might be accelerated, redirected (if the current path is not congruent with the goal), or otherwise enhanced.1