The challenge in thinking about policy as the product of a system lies in understanding
how policy makers translate sets of inputs into outputs. The major criticism of
Easton’s systems model is that most depictions of this model treat the political system
as a black box (that is, a system in which the internal workings are unexplained), rather
than opening the box to understand the processes that occur within it. A black box in
a systems model is something that performs a translating or processing function, but
where the actual workings of that system are unclear. The stages model of the policy
process is one way of opening up that black box to more thorough analysis.