DSpace administrators (and perhaps other roles) should be able to obtain reports on the review workflow, to answer questions such as:

• how many items were submitted (eg last month, or in a given timeframe);
• how many items were approved;
• how many items were processed in some way (even if they haven't been approved yet and/or were submitted prior to the report timeframe);
• what was the fastest/median/longest time from submission to approval;
• which reviewer(s) had tasks sitting in their queue for the longest time.

Some of this information may already be available via the workflow statistics module; however that module appears to be more focused on counting how many items entered each workflow state rather than eg processing times, identifying "slow" (or overworked) reviewers etc.