Impact risk is a measure of the certainty that an organisation will deliver on its proposed impact (as detailed in the impact plan). The question implied is: How sure is the impact plan to work, and what is the risk that the impact won’t be generated? Impact risk focuses in particular on the risk that the organisation’s outputs will not lead to the desired outcomes (see conditions for change), and the risk that the outcomes will be negated once adjustments have been made for the context of change (see context of change).
see 2.2 Impact Risk