Source. We find the district's board-approved student calendar on its official website. No third-party copies.
Extraction. Two independent automated readings of the document must agree on every date (first and last day, every day off).
If they disagree, a third reading decides, and unresolved cases go to manual review against the rendered document.
Plausibility rules. Instruction days are counted and compared with the number printed on the calendar; Thanksgiving, winter and spring break,
weekend dates and overlaps are checked.
Monitoring. We re-download every source regularly. When a district publishes a revision, the page is updated and the change is listed under
Corrections.
Confirmation. Districts and PTAs can confirm a calendar; confirmed pages say so.
