Standardisation is a statistical process that is designed to take account of two factors:
- The number of questions on a test paper and the time allowed for it can differ. If a Verbal Reasoning test has 80 questions and takes 50 minutes, while a maths paper has 100 questions and takes 45 minutes, simply adding the “raw scores” of the two together will not give equal weight to the results of both tests, and nor will an average. Standardisation is a way of giving equal value to the results of each test, regardless of the number of questions and the time allotted for completing them.
- The test scores must be adjusted to take account of their age at the time they take the 11+. One child taking the test might be born on the first day of the school year (September 1st) while another might be born on the last day (August 31st). With what amounts to a whole year’s difference in their ages, the older child is clearly at an advantage: as just one example they will have a whole additional year’s vocabulary, which the younger child will not. As children are exposed to new vocabulary at the rate of more than 1,000 words per year, the difference can be very significant for the 11+ tests. In order to remove this unfairness, the marks are adjusted to make them “standard” for all children, regardless of their age.
The age standardisation is carried out based on one of three options, which depends on the school’s requirements:
- Mean average score of 100 with a standard deviation of 15 – Most choose this option as this is the standard
- Adjusted mean with standard deviation of 15 – this is based on the number of qualifiers
- The same mean and standard deviation as previous years - the mean may be greater or less than 100 and the same applies for standard deviation
There are two types of banding:
- Band – This has, as far as possible, equal numbers of students in each of the bands.
- EI (Equal Interval) Band – The bandings of the standardised scores are as equal in size as possible. As the standardised scores follow a normal distribution you will have more students in the middle bands and fewer students in the top and bottom bands.