A model of the task setup, including the system class being tested, will be used in elaborating a detailed set of requirements from the basic quality characteristics we have identified. These requirements will be used in the derivation of reportable attributes and of measures and methods for arriving at values for those attributes.
For grammar checkers, the relevant task is the revision phase of the writing process. The agent and output types we recognise in this task are presented in the following task outline:
A non-proofed text prepared by the writer is revised by the end-user using advice produced by the system to produce a proofed text.In this model, the final output proofed text is an ideal result, which we can use to measure actual functionality.
In this particular mass-market system type, the writer and the
end-user are usually the same person. However, this is not
necessarily the case and the different roles are distinguished because
different characteristics of the person are potentially relevant to
each. The task outline given here and many of the elaborations of the
various components we give below are general to all revision-stage
setups, including spelling checking 
.
Relevant parts of the task model will include linked sets of descriptions:
