  Several researchers have argued that a machine learning system's
interpretability should be defined in relation to a specific agent or task: we
should not ask if the system is interpretable, but to whom is it interpretable.
We describe a model intended to help answer this question, by identifying
different roles that agents can fulfill in relation to the machine learning
system. We illustrate the use of our model in a variety of scenarios, exploring
how an agent's role influences its goals, and the implications for defining
interpretability. Finally, we make suggestions for how our model could be
useful to interpretability researchers, system developers, and regulatory
bodies auditing machine learning systems.
