What Happens in Practice?

PwC illustrates the relationship between level of assurance and time, effort, and cost.  Note that PwC also provides “assessment” on its graph.  However, an assessment is a consulting engagement.  In regard to sustainability reporting, assessment often results in suggestions for improvement of information systems or data collection and is not an assurance per se but will generally come before an assurance engagement.   An assessment by PwC is similar to the services that an internal auditor provides.