Parents often believe that Easter revision courses cram their children full of hitherto unlearnt facts, which are then duly disgorged in the summer's public examinations.
This is somewhat off the mark. Paul Redhead, co-principal of the Cambridge Centre for Sixth Form Studies, says: "There is no way, in a week, that we could cover the whole of the course.
"So the idea of cramming, force-feeding lots of information so that someone is bursting with it, then runs away and quickly disgorges it, just does not work on Easter revision courses."
As far as revising for A-levels is concerned, Mr Redhead explains, the idea is to cover the main points of the syllabus - so that students understand what happens when, and why.
Pupils are then left to do the detailed learning - for example, the names of parts of plants in biology - on their own.
The important thing, he adds, is to give students a conceptual framework to revise to, into which the finer details can be slipped later.
"Rather than its being something which is going to fill lots of gaps that a student may have," Mr Redhead says, "It tends to give them a shake- up and a framework for their revision until the June exams start."
This is reinforced during the revision week by lots of past exam paper practice, either in or outside class, depending on which school you choose to attend.
When choosing a revision course, parents and pupils need to be careful about asking how the college copes with preparing students for different examination boards - there are seven at present - and with revising for different syllabuses, set books, periods of history, etc.
Students also need to be clear about how the college structures its revision course days. Mr Redhead says: "At one extreme a course could consist of a small group of students being actively taught for eight hours a day, which sounds wonderful but is in fact killing.
"At the other extreme it could consist of a group of students sitting beavering away at their own work, while the teacher floats around helping individuals. In practice, most courses consist of a mixture of those two activities, and which is best for students depends really on what they feel they need.
"In terms of science, it tends to be taught. If one is dealing with, say English, you may well find that that is run almost like a circus, quite often with a couple of teachers and some students working away on their own, while others are being taught a set book that no one else is doing.
"That requires quite a lot of ingenuity, skill and confidence on the part of the teachers, to make sure that everyone is kept happy."
Some organisations offer Easter revision courses away from their own premises, using teachers they do not employ full time. Many of these courses are successful and perfectly respectable, but in some cases parents need to be sure that they are being offered good value for money.
Easter, Mr Redhead says, is a major chance to make significant inroads into revision and the pattern of revision that seems to work best is to go through the syllabus material several times before the June exam, rather than go through it once, slowly, over eight weeks.
Attention also needs to be paid to revision skills and mark gaining skills. The standard way of reading through your notes may become ineffective and tedious after a while. There are several techniques to enliven the process. For example :
l Take a blank sheet of paper and a specific topic. Then, within a set period of time, write down key words signposting everything you can remember about that topic.
When you have finished, open your revision notes and read them through to see what you have remembered and what you have forgotten. This technique distinguishes what the student genuinely knows from what is only vaguely grasped and highlights what needs to be concentrated on.
l Take an A4 sheet of paper and write down the name of your chosen area of study, say, proteins, in the centre of the horizontal page.
Now draw lines off it leading to other headings, for example protein function, structure, synthesis. From these sub-headings further lines branch out to, for example, functions of muscle, oxygen, transport, etc.
This forces you to think about the relationship between ideas; exams are very much about forcing people to find new ways down pathways and finding new relationships between topics.
It is also important to practice exam techniques. On the one hand, students need to get battle-hardened. "Like soldiers on manoeuvres, you can learn all you like about the theory of war but if you are squirming through a mud-filled trench with bullets being fired over your head it is different," says Paul Redhead.
On the other hand, students do need to practise essay planning. You need to be able quickly to summarise the main points you wish to make before you start writing.
Another key point about answering papers in which all the questions are compulsory is that you should read through the entire paper before starting to write your answers.
If you don't, the danger is that the first question may be the hardest, and you could get stuck and demoralised trying to answer it. If you start on an easier question you can come back to the first question later.
It is also important to be aware of maximising the number of marks you get per question. Even with short answers, you should be sure to give full explanations so as to get marks.
In the end , the value of Easter revision courses often comes down to instilling confidence in the student. Paul Redhead says: "If someone comes away thinking, `yes I am well into the revision. I have started. I am feeling in control. I think I can do it in the time', it's the kind of thing that a lot of students will tell you is as much a feature of a successful course as actually having learnt lots."Reuse content