The residual risk for an engagement shows in the Residual Risk field in the Engagement Summary area of the engagement page. This field only shows a value if the engagement has at least one associated issue with a residual risk rating. Otherwise it is blank.
The residual risk for an engagement is the highest residual risk rating of its associated issues. Associated issues include not only the issues raised for a particular engagement, but also issues raised for vendor- or service-level controls in previous engagements that required the same control and that include the same supplier (for vendor-level controls) or commodities (for service-level controls).