MOSS provides SharePoint administrators with the ability to view XML-based reports on workflow usage. Each workflow generates the following reports:
Activity Duration Report: This report provides information about the duration (in hours) for which a particular workflow ran before completion.
Cancellation and Error Report: This report provides information about the workflows that didn't run because they were either cancelled or encountered an error.
The SharePoint site user interface allows administrators to open these XML reports in Excel for review and analysis.