No absolute results can be obtained with SIENA, however, because as a simulation of a typical urban area it is not universal and directly representative of every real-world setting. Instead results need to be interpreted as being indicative of what is likely to happen in the real world. SIENA allows problems to be defined or highlighted which, in consequence, can be more specifically addressed when translated into a real-world setting. The same problem is inherent in all prognostic health risk or impact assessments, for these are based not on predictions of what will happen, but on scenarios of what might happen. In the same way, these scenarios are indicative of a number of plausible states, none of which is likely to represent exactly the actual situation in a specific area.