The pressure of choosing a degree in a final-year classroom is considerable. Students are told that a field chosen at eighteen decides a lifetime. But looking at how universities actually work, enrolment does not lock in a field. There are several more doors.

Of course, a door existing and a door opening easily are different things. It is better to know each threshold precisely.

Transferring — the places are fixed

Transferring means changing your department. Your enrolment itself moves, so the field on your degree certificate changes.

The threshold is high because of caps on numbers. Universities limit outgoing and incoming transfers to a set proportion of each department's intake. It is permitted only within the range set in the regulations, and transferring into a popular department means competing for those limited places.

On top of that come year requirements and grade requirements. Usually only students who have completed a certain number of semesters may apply, and selection is by grades. In other words, first-year grades become the qualifying condition for transferring. Drifting through the first year on the assumption that "I will just transfer if it does not suit" closes the very door you were counting on.

Double major — a wide door with a heavy load

A double major means completing another field while keeping your original one. Selection criteria are often more relaxed than for transferring, making it the most realistic of the three to get into.

There is a price, though. The credits you have to complete increase. Meeting the graduation requirements of both fields means a heavier load each semester, or graduating later.

Applications usually carry conditions on the number of semesters already registered, a minimum number of credits earned and grade point average, and where places are limited, selection is by grades. Deciding late can therefore push you out of eligibility.

A similar but distinct route is the minor. It requires fewer credits than a double major and is recorded differently on graduation. The choice depends on whether the purpose is a qualification or an experience.

Lateral entry — an examination to change university

Lateral entry means entering the second or third year of another university. Unlike the previous two, it involves a separate admissions process.

Most universities use an English written examination as the basic method. At leading universities this is joined by an in-depth subject test or an interview, and documents are sometimes required. It is closer to a second round of university entrance, with its own preparation time and cost.

You also need to check how many credits are recognised. How much of what you studied at the previous university carries over decides how long graduation takes.

So how should you approach choosing a degree?

1. Do not choose carelessly on the basis that it can be changed. Both transferring and double majors take first-year grades as a qualifying condition. Letting grades go because you are not interested closes the doors with them.
2. Check that university's regulations before applying. Transfer quotas and double major requirements differ by institution. The same scheme can have entirely different conditions.
3. Note whether the move is within a field or across fields. Crossing fields, from humanities to engineering for instance, is far harder because of prerequisite requirements.
4. Look at the curriculum rather than the department name. Doing this check before enrolment reduces the need to move at all. How to do it is set out in Choosing a Major.

In summary

Enrolling at university is not the final fixing of a field. But the doors that are open come with conditions attached — grades and timing. Transferring has fixed places, a double major is a heavy load, and lateral entry is another entrance exam. The options available to a student who spends first year knowing this, and to one who does not, look entirely different by second year.