Parents should probe beneath the surface when visiting schools

If you're planning to visit an independent school's open day, do not simply admire the facilities but look beneath the surface. Try not to be over-impressed by splendid language laboratories and Olympic-size swimming pools, warns the Independent School Council (ISC); instead, pay equal attention to the staff and pupils.

While first impressions are important, and school buildings contribute to the atmosphere of a school, the idea is to discover what happens inside them. And to find this out you need to talk to children, teachers, senior staff, and, if you're lucky, to the parents as well.

The UK has 2,500 independent schools and on average parents look around two years before their child attends. This normally means going to an open day, at which parents are addressed by the head, given school tours and a chat with staff. Some schools, however, run open days by invitation only. The Cheltenham Ladies' College, for example, has around ten open days a year, but open day booking forms need to be completed a month before a visit.

This year Headington School in Oxford will hold one "free for all" and one invitation only open day per term when parents are allocated a normal working day on which to visit. The general open days are good for people who want to be anonymous and look around without any feeling of commitment, says marketing director Laura Douglas.

Parents are shown around by a sixth-former, both at open days and private visits, which Douglas says parents like because they can get straightforward answers to their questions. School tours can be a chance to find out more about pastoral care. Douglas suggests asking a pupil if they were unhappy whom they would talk to, or "if someone was being horrid to a friend where would they turn?" But keep the questions subtle, rather than interrogating. The ISC stresses that it's a good idea to try to speak to pupils without the head or staff present. If pupils are not prepared to stop and help you, then alarm bells should start to ring.

As you go round the school, try to get a feeling for how pupils and staff work together and what the discipline is like. Ask how many children have been expelled over the past five years and for what? Douglas's advice is to "look into the rooms you've walked past, linger, be aware. Obviously we want to show the newest science block, but you can learn a lot by looking at notice boards. Are they interesting and up to date? Is a lot happening, both work and play?"

The Mount School in York, a Quaker girls' boarding school, holds five open days a year when parents can observe lessons and ask teachers questions. Marketing assistant Sandra Parker says it's a good idea to jot down any questions in advance, but the usual ones include information on boarding arrangements, the number of pupils, the percentage of overseas students, what subjects are offered at A-level and class sizes. Class size is a hot topic. One of the main reasons people choose independent schools is because of small classes, says the ISC. The average class in the state sector is 30, while prep schools have 15 to 20.

Most visitors at open days are keen to meet the head, although the ICS warns that you should not expect heads to be super-salesmen or saleswomen. They need to convince you that they will really care for your child, explain why their school could be the right one and be prepared to answer questions fully and frankly. But as the head might not be at the school throughout your child's career, don't choose a school just because you like the head. Douglas says you need to find out what makes a head tick, but a machine gun rattle of questions is not the best approach. Instead, try questions like, "what sort of child wouldn't be happy at your school?"

When it comes to teachers, find out what the turnover is like and if the school has difficulty attracting teachers in certain subjects. Ask to be taken into a few classrooms while teaching is in progress. You shouldn't disrupt a lesson, but as you're paying for the teaching you will want to know what it's like. The last word from the ISC is this: don't choose a school on the basis of an open day; instead go back when it's operating normally and have another look.