Validate data entry patterns

Set up data validation on the 'Student Grades' sheet: enforce email format in column B, restrict column C to the list Present, Absent, Late with a dropdown, and ensure column D accepts only dates in YYYY-MM-DD. Apply custom error messages explaining the allowed format and prevent invalid entries. Run a test by entering 'john at example' in B5 and '13/31/2026' in D6 and show that both are blocked.

Before I hand this sheet to teachers, make the validation teacher-friendly: move the rules into a visible 'Validation Rules' sheet with examples, add user-friendly error messages explaining how to fix common mistakes, make dropdowns robust to capitalization variations, and suggest one lightweight script to auto-correct common typos. Flag any validation that will block historic data and advise how to migrate it.

I added strict validations for attendance and emails, but teachers keep pasting bulk updates that bypass rules and our dashboards stop updating. I can't tell whether to train them on paste methods, restrict editing, or adjust validations to accept pastes. What is the likely diagnosis and the best immediate change that prevents breakage without slowing teachers down this week?

Every term we spend a day cleaning up student lists because teachers paste inconsistent emails, dates, and statuses and our term-level reports break. What long-term changes to sheet design, validation, and workflow will stop this cycle—should we use forms, stricter edit permissions, or a pre-import cleaning step—and how do we choose among those for a small school with little IT support?