Psychologist's formula for ideal Xmas toy

The stores are awash with all the latest must-have toys and games at this time of year and, as anyone who has visited a large toyshop will know, finding the right gift for the youngsters can be a minefield. Thankfully, every parent's prayer has been answered by one Dr Cliff Arnall.

Top toy searches:
  1. Transformers toy
  2. Monopoly board games
  3. Cuddly toys
  4. Toys baby dolls
  5. Childrens dolls
  6. Plush toys
  7. Bratz dolls
  8. Action man car
  9. Ben 10 alien laboratory
  10. Lego pieces
Dr Arnall, a psychologist whose previous calculations have enabled us to find the happiest or most depressing day of the year, believes that maths can be used to work out the "play value" of this year's festive purchases. But hold your horses there, folks. Before you rush out to the toy store, you'll be needing a calculator.

Firstly, you'll need to assess the toy against six criteria: usefulness for playing alone (Pi); playing with others (Po); whether it encourages creativity (Cr); its value as a means of promoting social interaction (S); its general utility (U) and whether it will be any good as a hand-me-down (H). Now give your chosen toy a score out of five for each of those criteria and then add the scores together.

Then, in a separate sum, estimate the amount of time in hours your child will play with the toy regularly (T) and multiply this by how many months its interest will remain (L). These two figures should then be divided by the square root of the cost (C) and added to the total score from the criteria you calculated earlier.

Let's run through that again – T x L + Pi + Po + Cr + S + U + H/square root of C... got it?

Dr Arnall admitted to The Telegraph: "A toy may score higher for one child than another but that's an important part of the exercise."

Or you could just try asking your excited tots to write a list for Santa! Let us know what you think. Will you be using a calculator for the perfect toy?