The practitioner responds to an assessed risk in an estimate through one or more of these: looking at events up to the report date for evidence; testing the way the estimate was made and the data behind it (method, assumptions and how reliable the data are); testing the controls over how it was made alongside other procedures; and building an independent point estimate or range against which to judge the responsible party's figure.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.