Simile's visual modelling environment is based on the widely-used System Dynamics notation, involving the drawing of stock-and-flow and influence diagrams. Both concepts are intuitive, and thus readily learnt.
Simile adds on to this a concept of objects, which are simply submodel boxes drawn around other model elements and given the property of having multiple instances. These can be nested to show the notion of containership in an obvious manner. Simile's ease of use reduces the barrier for researchers to get on with modelling. Whether they wish to implement a published model, work with a Simile model provided by a colleague, or develop new models from scratch, the learning effort is much less compared with programming, and the time required to produce models greatly reduced even for the competent programmer. Simile's ease of use also makes it very suitable for teaching. Even if your aim is simply to give the students a pre-built model, it is beneficial for them to see this as the model diagram, rather than being given separate documentation for a black-box programmed model. Simile has been used successfully in class model-design exercises, with groups working on submodels which are then combined to make the whole model.