A timetable that survives contact with reality

The timetable is the most quietly important artefact a school produces. Attendance hangs off it. Teacher workload hangs off it. Room conflicts, cover arrangements, parent expectations, the ability to say with confidence where any child is at 10:40 on a Wednesday — all of it hangs off the timetable.

And in most schools it is a spreadsheet that was correct once, in September.

Why timetables rot

They rot because reality edits them and nobody edits the file. A teacher goes on leave and a colleague covers period four. A lab is out of use for a fortnight and two classes swap rooms. Grade 10 splits into sets after the first assessment.

Each of those is a five-second decision in a corridor and a permanent divergence between the published schedule and the actual one. By half-term the printed version is a historical document, and any system reading from it is producing confident, wrong answers.

Build it out of periods, not times

The first structural mistake is storing lessons against clock times — "Maths, 09:50–10:35". It looks fine until the school runs a shortened Ramadan schedule, or an exam week, or an assembly Monday, and every single entry needs rewriting.

Store lessons against named periods instead — Period 1 through Period 7 — and define the clock times separately, per day pattern. Then a shortened day is one change to the day pattern, not four hundred changes to the timetable. Every downstream feature keeps working, because "Period 4 on Wednesday" is still true regardless of what the clock says.

Make amendments first-class

The cover arrangement is not an exception to the timetable; it is the timetable for that day. If your system cannot record "Period 4, 10B Maths, taught by Ms Haddad instead of Mr Salim, in Room 12 instead of the lab", then that information will live on a whiteboard in the staff room, and:

• attendance for that period will be filed against the wrong teacher,
• the parent portal will show a lesson that did not happen as scheduled,
• and your workload reporting at the end of term will be fiction.

A timetable that cannot be amended in place will be amended somewhere else. That is the whole failure mode.

Print is not a nice-to-have

We shipped PDF export for class schedules because of a piece of feedback we initially misread. A deputy head told us the timetable "needed to work on paper". We assumed this was habit. It was not.

Paper timetables get pinned to classroom doors, handed to substitute teachers who do not have accounts yet, given to parents at induction evenings, and taken into exam halls where phones are banned. A schedule that only exists on a screen is a schedule that is absent in exactly the situations where certainty matters most.

So the printed version has to come from the same source as the screen version, carry the school's own logo, and be regenerable in one click after every amendment. Otherwise somebody prints it once in September and you are back where you started.

The test

Here is the question we ask schools to answer about their current timetable:

It is 10:40 on a Wednesday in week 9. A parent calls and asks where their child is right now. How long does it take you to give an answer you would be willing to stand behind?

If the answer involves walking to the staff room, your timetable has already rotted. It is week 9, not week 1 — the September version is not the question.