Incorporating differentiators in the task-based model

To sum up so far, both the task you decide to set candidates as well as the two factors described in the last section - guidance level and language level - will be influential when choosing which interaction to use in your test question. 

In the approach adopted in this course, your chosen task type is taken as a starting point. However, as we saw in the sections on the four task types, there is not just one interaction which can be used to construct a test question of a particular task type: for each type, you have several possible interactions at your disposal. Your choice between them will depend, therefore, on other things. 

The factors guidance level and language level can be incorporated into the task-based model and used as differentiators; they serve well as axes along which interactions can be plotted (and therefore distinguished from others). In other words, they can help you choose between the interactions available for a particular task type.