Parents of the 600,000 children (in England) who will change schools next September have until October 31 to make their choice.“This can be very stressful and some parents feel so anxious they begin to doubt their capacity to make the right decision,” Susan Hamlyn, director of The Good Schools Guide, says. “They see the schools, they do their homework, but there’s so much gossip, rumour and pressure among other parents it can be hard to focus on what’s important.”

Here are the key points parents should consider, according to the experts:

See the school during the day
Visit the school during the day and you’ll get a better sense of what it’s really like rather than the marketing spin from a heavily orchestrated open evening. “Are you seeing attentive faces in class? Look at the work on the walls — has an effort been made? What’s behaviour like at the end of a lesson? Are uniform rules enforced?” says Janette Wallis, an adviser at The Good Schools Guide.

“Choosing a school is like house hunting — there’s a chemistry,” says Katie Krais, an education consultant at JK Educate. “Go with your instinct. If you can’t see your child there, don’t even consider it.”

Understand what the school’s GCSE results really mean
If you’re hoping your child will go to university, looking at the standard five A*-C grade GCSEs, including English and maths, which many schools trumpet, is of limited value (national average: 57 per cent). Ask instead what proportion get A*s and As; a good score for a genuinely comprehensive school is upwards of 30 per cent. Figures from the Independent Schools Council show 62 per cent of grades are A* or A.

Good GCSEs are vital because they have been the only measure universities have had to go on since the decision was taken to abolish AS levels. If you think your child may eventually try for a top university, they’ll need mostly As and A*s. “One chemistry tutor at Durham University told me that they are looking for reasons to turn people away, and a B-grade in GCSE English wouldn’t affect their studies in chemistry, but it was what they had to do,” says Charles Bonas, an organiser of the Independent Schools Show, held in London in November.

Ask the head about ‘Progress 8’
And look out for the government’s new school performance measures this year. Progress 8 measures pupils’ progress from entering the school in Year 7 (based on their Year 6 Sats scores) to their GCSE results in eight subjects, and compares them with the national average for a child with the same academic starting point. Provisional results for all schools are published on October 13: scores will range from -1 to +1; anything above zero means the school is doing OK; below zero means their pupils aren’t achieving the average GCSE grades of similar pupils nationally. Some schools opted in to Progress 8 last year, so it’s worth asking at the open evening.

Ask where the children move on to
Most schools will give you a list of leavers’ destinations: ask for the last three years of lists, advises Wallis. Are these the kinds of places you could see your child attending? “You want to see that able pupils are going on to good universities. If you are an ambitious parent and have a bright child, it’s not ideal if you don’t see a clutch of children going to Russell Group universities. Your child may not be one of them but you want to know that it’s possible.”

Is it a good school that’s just coasting?
There is a lot to be said for catching a school on the up. A school with an Ofsted rating of 3 (requires improvement) with a visionary new head might be a better bet than a steady 2 (good) that hasn’t changed for years.

Parents agonise most when faced with a fair-to-middling school on paper because it feels like you’re taking a leap, says Dr Lee Elliot Major, chief executive of the education charity the Sutton Trust. “Remember that state schools have improved immeasurably in the past two decades, so unless the school has real problems, your child can still get the As. You’ll have to be hands-on, challenging the school on their teaching if necessary and possibly topping up with tutoring.”

Ask as much as you can about the teachers they recruit
After their own family background, quality of teaching is what makes the biggest difference to a child, and no one type of school has a monopoly on good or bad. Ask where the teachers in a school qualified — and whether they have degrees directly related to their subjects, particularly tricky-to-fill ones, says the education consultant Lisa Freedman from attheschoolgates.co.uk. “Find out who teaches physics, for example. Do they have a physics degree?”

Is the sports team just for the best pupils?
An impressive list of extracurricular activities is all very well, but how many pupils take part? If there’s an orchestra, do they go on tour or play concerts? Is there just one sports team for the best 11 or does everyone get a chance?

Remember that the decision is yours, not your child’s
Children should have a say in their choice of school, but not the final one, says Krais. “Of course you want to take their feelings into consideration, but ultimately, you are the adult and they are ten years old.”

Remember, where the child’s friends are going is far less important than the average ten-year-old thinks it is.