‘Like a jigsaw puzzle’: The challenging task of generating school timetables

‘Like a jigsaw puzzle’: The challenging task of generating school timetables

Preparing school timetables is a complex task - soon to be made even more complicated with the rollout of full subject-based banding in secondary schools from 2024. But despite the added challenge, these teachers remain optimistic.

Timetabling committee 1
Pei Hwa Secondary's timetabling committee member Ms Teo Si Hui, SBB coordinator Mdm Yang Ser Yee, and head of timetabling committee Mr Wong Liang Soon. (Photo: Lianne Chia) 

SINGAPORE: It might seem like a routine chore - and one that could easily be generated by a computer.

But preparing school timetables for students and teachers is in fact a complex task, requiring meticulous data entry, manual adjustments and even a fair amount of creativity from the team of teachers in charge of the task. And with the rollout of full subject-based banding (SBB) in all schools by 2024, some schools say this already complex task is set to become even more complicated.

In March, Education Minister Ong Ye Kung announced that the current system of streaming, where students go into the Normal (Technical), Normal (Academic) and Express streams based on their PSLE results, would be replaced by full SBB, where students take different subjects at different levels according to their ability.

The model was prototyped in 12 secondary schools in 2014, where students in the Normal (Technical) and Normal (Academic) streams can take English, Mathematics, Science or Mother Tongue Languages at a higher level if they perform well in these subjects at the PSLE.

This was later rolled out to all secondary schools in 2018.

The increased flexibility for students, however, also meant that schools have had to exercise their creativity in coming up with customised timetables to cater to the many different subject combinations each student took.

READ: ‘Their best friends are from different streams’: Why this school did away with traditional form classes 


Prior to the introduction of SBB at Jurong West Secondary in 2014, timetables took at most about a week to a week and a half to generate, according to a member of the school’s timetabling committee Ms Orry Zhang. Today, however, this process takes about three weeks on average. 

Ms Zhang, who is also a Chemistry and Literature teacher, explained that the timetabling process usually begins towards the end of the preceding school year, over the school holidays.

The school uses a software to generate timetables that show the lesson periods scheduled for all the classes every day. But prior to this, she said, manual data entry is required to create each individual lesson period, where details such as subject teachers and venue has to be entered before the actual generation can begin. 

Logistics considerations aside, timetabling committees also need to take into account issues such as the welfare of teachers, the comfort and suitability of each teacher to straddle different levels and subjects, as well as the ability of students to focus and learn.

At Pei Hwa Secondary, which is also one of the first 12 secondary schools to implement SBB in 2014, the timetabling committee tries to offer students more double period lessons of 70 minutes. This is so, explained timetabling committee member and chemistry teacher Teo Si Hui, that students have fewer subjects per day, which would allow them to consolidate their learning better.

“With a double period, some of the learning spaces - such as the computer labs - can also be better optimised,” she said.

Then, there are various other considerations that would need to be factored in and included. These could be limits on the number of consecutive periods each teacher can take, or lessons, such as science practical lessons, requiring a particular venue.

“It usually takes quite a number of days to do all the data entry, because we really need to make sure everything is correct with no mistakes,” said Jurong West’s Ms Zhang, adding that it would be laborious to unravel the mistake once the software has started running. 

“The more constraints we set, the more difficult it is for the timetable to generate,” she added.

To ease the process, Pei Hwa’s Ms Teo added that the school uses past data and experience - such as the number of students taking each subject at the different levels - to generate a preliminary timetable, which will be finalised after confirming the Secondary 1 posting information. 

It takes about six hours for the software to run before a draft timetable is generated, following which the committee would then need to make manual adjustments to the timetable to resolve remaining conflicts, which are represented by loose cards at the bottom of the timetable that need to be individually dragged into the generated timetable.  

This, said Ms Zhang, is where creative solutions need to come in.

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A draft timetable at Jurong West Secondary. The coloured "cards" at the bottom represent the conflicts, or "collisions" that need to be manually adjusted. (Photo: Lianne Chia) 


Committee members from both schools stressed the importance of having creative ideas and solutions to make these manual adjustments.

For instance, Jurong West made the decision to place subjects with fewer students at the end of the school day, so the majority of students would not need to stay back.

“That’s one way we look after the welfare of the students,” said Ms Zhang. “To ensure we are not taxing the other students, while allowing our students to learn and develop all the ways that they can.”

She added that the committee had to accept that some things would have to give, in order to optimise the timetable for all students and teachers.

“Things were initially quite neat prior to SBB … such as the dismissal timing,” she said. “But now, we’ve had to accept that it might not be so clean-cut.

“We could have classes ending at different timings, so some would end at 3pm, while others would end at 3.35 ... we just had to accept that the timetable won’t look so “neat” anymore,” she said.

Creating more venues for lessons, too, is one other possibility.

“Special rooms, such as music rooms, which are not being used outside of music lessons, can become multi-purpose if we just add a few tables and chairs,” said Mr Wong Liang Soon, another member of Pei Hwa’s timetabling committee. “We also have a few classrooms with partitions, so we can use that too, to create new venues.”

“There are also teachers who like to use the open spaces in the school for lessons,” added Ms Teo. “Like if the lesson’s a drama, they don’t need tables and chairs, so they bring the students to the foyer.”


With the implementation of full SBB, students would also be able to take humanities subjects at different levels. And this, said both schools, would undoubtedly further complicate the timetable generation process.

But Jurong West’s Ms Zhang noted that the primary ideas and concepts remain the same.

“We’ll still need to be flexible and creative in the way we deploy teachers, we still need to be mindful and plan in advance for venues, and of course we will also need to continue leveraging on our Education and Career Guidance programme, so the students make informed choices,” she said.

“We hope that some of our past experiences can help us,” added Choy Chee Ping, Jurong West’s second-in-charge in the timetabling committee. “It helps that we’re not starting from scratch.”

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Jurong West Secondary's timetabling committee second-in-charge Mr Choy Chee Ping, in-charge Ms Sharron Chiam (centre) and member Ms Orry Zhang (right). (Photo: Lianne Chia) 

The teachers from both schools, however, also highlighted the importance of getting input from other schools.

“It would help a lot if MOE could facilitate the exchange of ideas across different schools,” said Pei Hwa’s vice principal Philip Tan. “Because what we really need is ideas.

There might be other schools that might have done things we’ve never tried out before … so it would be good to learn.”

“We can only come up with so many ideas,” added Yang Ser Yee, the school’s SBB coordinator. “More brains are definitely better.”

It may be a complex task ahead of them, but the teachers remain optimistic.

“It’s hard work, but we’ve seen a lot of success stories,” said Jurong West’s Ms Zhang. “That’s one factor that really keeps us going.”

“It’s like fixing a jigsaw puzzle … challenging, but interesting”, added Mr Choy. “It’s not about the complexity, but about whether we can find the right formula or combination.”

“Sometimes, it just clicks.”

Source: CNA/lc