A site-wide performance report is dragged down by sections nobody intends to optimise — a legacy archive, a customer login area, a documentation subfolder from an old product.
Removing them from the analysis
Filter out the URLs starting with those paths. The remaining figures describe the part of the site the work actually covers.
Why this is not cheating
Reporting a site-wide average that includes a section deliberately excluded from the programme misrepresents both the problem and the progress. What matters is stating clearly which sections were excluded and why.
Keep the excluded set visible
Report it separately rather than deleting it. A legacy section performing badly is still a real thing on the site, and it may be worth a decision — remove it, redirect it, or accept it — rather than quietly dropping it from every report.
Try it: Remove Lines Starting With on SeoWolf's Notepad.