School timetable

A school timetable is a table for coordinating these four elements:
* students
* teachers
* rooms
* time slots (also called periods)

School timetables usually cycle every week or every fortnight. The phrase "School timetables" largely refers to high schools, because primary schools typically have trivially simple structures.

High school timetables are quite different from university timetables. The main difference is the fact that in high schools, students have to be occupied and supervised every hour of the school day, or nearly every hour. Also, high school teachers generally have much higher teaching loads than is the case in universities. As a result, it is generally considered that university timetables involve more human judgement whereas high school timetabling is a more computationally intensive task, see constraint satisfaction problem.

Terminology

There are large differences in terminology between different english-speaking regions, depending on the system of secondary education used. The following terms usually have a special meaning in the context of high school timetables:

* Class: A set of students who regularly meet the same teacher to study a particular subject. For example, the 8A Maths class. In schools where students can not choose their curriculum, class can also mean a group of students of the same age that share a common timetable.
* Course: A particular subject studied at a particular level, for example Year 8 Maths.
* Lecture or Lesson: A meeting between (usually) a single teacher and a class of students which takes one period and is a part of a certain course.
* Period: A time interval within the teaching cycle within which a lesson can be scheduled, and which is the smallest such time interval. For example, "Monday third period". Periods are usually from 45 to 60 minutes long (up to 80 minutes in Canada), depending on the school, and have breaks of various lengths between them. Also sometimes called a time slot.
* Block: This term is ambiguous, but in this article it refers to a set of lessons of different courses that must be placed concurrently.
* Student body: A set of students who are timetabled together, for example the 8A roll-call group.
* Band (or Cluster): A set of classes involving the same student body, which are therefore horizontally linked, meaning they must be on separate periods
* Year group or Year level: A set of students at the same stage of their schooling, for example Year 6.
* Elective Line: A block of many classes of many subjects such that each student may choose one subject from the line.

Types of School Timetables

Primary schools typically have timetables, however the timetable is usually so simple that they can be constructed manually or in Excel.

In some countries, such as China and Peru, high school students are not given any choice in subjects, and this makes timetabling easy - e.g. the students can remain in the one room all day while the teachers rotate.

In other countries, such as USA, the whole school is typically run on a system of units, where each subject has the same number of lessons per cycle and subjects are placed into 'lines'. This also makes timetabling easy. Other schools use block scheduling.

In other countries, such as Australia and most European countries, timetables can be extremely difficult to construct. The process can take weeks of effort and typically computers are needed in the process.

Problems and Issues Involved

The task of constructing a high school timetable involves the following issues (not an exhaustive list):
* Assigning periods to classes. There is a need to spread out lessons across the teaching cycle as much as possible, e.g. to avoid having 3 lessons on the same day or most of the lessons in Week One of a 2-week cycle.
* Some classes need 'double periods' (2 consecutive periods). This especially happens with practical lessons such as science lab work or art classes where it takes a long time to set up equipment.
* Assigning teachers to classes ('staffing'): sometimes the department head teachers stipulate what the staffing will be, but often there are alternative teachers that can be given to a class, and the timetabler must make the decision based on timetabling considerations.
* Assigning rooms to classes. Some subjects require specialist rooms, e.g. science labs.
* The last period of a day is often less desired and these must be shared fairly across all classes
* Some schools assign the same number of periods to all subjects, but more commonly (at least outside USA) there are a variety of lengths of classes: 9 periods per cycle, 8, 7, 5 and so on. If this is the case, it means that it's not possible to have a 'coherent' structure to the timetable. 'Coherent' means that the classes in each year up neatly with classes in other years in school-wide 'super-columns'. Non coherent timetables are much more difficult to construct.
* Occasionally there is 'vertical integration': a class from one year has a requirement to line up with a particular class from the next year. This happens mainly when students are allowed to take subjects in a higher year level.
* Individual teachers have 'unavailabilities': periods when they are occupied in external or non-teaching tasks and therefore cannot teach on those periods.
* Part-timer teachers need to have certain entire days off. They will either specify to the school which weekdays they are or simply how many days per cycle they need off. Such teachers can greatly add to the difficulty of timetabling when they are assigned to large blocks.
* Sometimes two schools try to coordinate their timetables in order to be able to share a small number of staff. Often the schools have different bell times. Often also there is travel time between campuses which must be taken into consideration.
* Sometimes a school is spread over 2 or more campuses, and the timetable should minimise the amount of cross-campus travel for students and teachers. Furthermore, where travel occurs, the travel time must be taken into consideration.
* Sometimes there are constraints imposed from external organisations, such as sports venues bookings or technical education for senior students.
* Sometimes there are 2 or 3 subjects which rotate between student bodies throughout the year. For example, the 8A students might take Art in the first half of the year and Music in the second half.
* Classes should be assigned rooms in a way which attempts to give the same room to the same class for all or most lessons ('room constancy').
* Sometimes it is unavoidable to have what is known as a 'split class': this is a class where one teacher takes it for some lessons and another teacher for other lessons. This can happen e.g. because no single teacher is available on all scheduled periods, or because no single teacher can take it without going over their maximum teaching load. Another definition for a split class is when a teacher must teach two different grade levels in one period (for example Grade 10 French and Grade 11 French). This often occurs with less popular subjects, which are not big enough to be made into separate classes. Split classes are highly undesirable, especially in private (well funded) schools.
* Off-timetable lessons: sometimes an occasional lesson is scheduled "off the timetable" meaning before school or after school or during lunch. This usually happens with older students. It can be a desperate response to intractable timetabling problems or a compromise reached in order for the school to be able to offer less popular subjects.

External links

* [http://directory.google.com/Top/Computers/Software/Educational/Administration_and_School_Management/Scheduling_Utilities/ Google list of scheduling software]
* [http://www.asap.cs.nott.ac.uk/patat/patat-index.shtml PATAT Conferences] The International Series of Conferences on the Practice and Theory of Automated Timetabling
* [http://www.shambles.net/pages/staff/TTsoft Another directory of software products]
* [http://gstpl.wikispaces.com/Timetabling+Software+Survey Software list] of open source, freeware and commercial applications for school and university timetabling. The list includes e.g. prices, features, algorithms, ...
* [http://www.cs.qub.ac.uk/itc2007/index.htm International Timetabling Competition 2007] (Note: URL's to commercial companies ("linkspam") will be promptly removed. These links belong in the directories above).