A school running the British curriculum in one wing and the American curriculum in the other does not have two timetables. It has one timetable with two sets of rules, and the difficulty is entirely in the places where the two sets touch.
The touching points are the shared resources. The sports hall does not belong to a curriculum. Neither does the science lab, the bus schedule, the canteen sitting, or — most consequentially — the Music teacher who covers both programmes because there is only one of them. Timetable each curriculum independently and every one of those shared resources becomes a collision waiting to be discovered.
This is the first thing that breaks tools designed for a single national curriculum. They assume one set of subjects, one set of period structures, one progression. Point them at a school running IGCSE alongside the IB Diploma and a French section, and the model does not have a place to put the second and third structures.
The second difficulty is that curricula genuinely disagree about the shape of the week. Required contact hours differ by subject and by programme. The IB Diploma has specific hour requirements at Higher and Standard Level. A French section following the national programme has its own. British A-Levels assume a different distribution again. These are not preferences to be balanced — for accredited programmes they are requirements, and a timetable that quietly under-delivers on them is a problem that surfaces at inspection rather than in week one.
The third is language streams, which multiply the constraint count in a way that is easy to underestimate. A subject taught in Arabic to one group and English to another is two lessons requiring two differently-qualified teachers, even though it appears once on a subject list. Schools that treat the bilingual dimension as a labelling exercise rather than a scheduling one tend to discover the gap when they realise the Arabic-medium Science group has been assigned to a teacher who does not teach in Arabic.
The fourth is the week shape itself. A school in the Gulf running Sunday to Thursday alongside a programme with expectations built around a Monday-to-Friday calendar has a genuine structural constraint, particularly where external examination timetables or partner-school links are involved. Tools that treat Monday-to-Friday as an assumption rather than a setting force a workaround, and the workaround is usually a spreadsheet running alongside the system.
The fifth is multi-campus, which adds a dimension most single-site tools do not model at all: travel time. A teacher shared between two sites cannot teach period three at one and period four at the other if the sites are twenty minutes apart. That is not a clash by any conventional definition — the teacher is in one place at a time — but it is impossible, and it will be discovered by the teacher.
The approach that holds up across all five is to stop treating the curriculum as the organising unit. Model the school as one pool of resources — teachers with their qualifications and languages, rooms with their capacities and equipment, a calendar with its days and periods — and treat each curriculum as a set of requirements drawing on that shared pool. The shared Music teacher then has one schedule rather than two, and the conflict cannot be created because there is only one of them in the model.
That reframing also makes the accreditation question answerable. If required contact hours are constraints in the model rather than assumptions in someone’s head, "does Year 12 IB receive its required Higher Level hours" is a check the system performs rather than a spreadsheet someone maintains in parallel.
It is worth naming the part that does not automate. Deciding that the Year 11 IGCSE cohort takes priority over the Year 9 French section for the good lab slot is a values judgement about the school, and no software should be making it. What software should do is make the trade-off visible — showing that the two requirements genuinely compete and that satisfying both is not possible — so the decision is made deliberately by someone with the authority to make it, rather than falling out of the order in which lessons happened to be placed.
Skoolia was built for schools running more than one programme: multiple curricula against one shared resource pool, any week shape including Sunday-to-Thursday, language as a teacher attribute rather than a label, and scheduling across campuses. The timetable generator works from the shared pool rather than per-curriculum, and the resulting schedule feeds the same attendance, gradebook and parent portal regardless of which programme a student sits in.
The mistake worth avoiding is the intuitive one: timetabling each curriculum separately and reconciling afterwards. Reconciliation is where the shared Music teacher gets discovered, in August, by which point both timetables are finished.