Understanding Standardised Scores: A Basic Guide

Misunderstandings often arise around the 11 Plus, particularly around the terms “standardised score” and “age standardisation”. Many parents find it baffling how a test with 80 questions can result in a final score such as 130.

This guide aims to provide a straightforward explanation of score standardisation. A more in-depth technical explanation is also available for those interested in delving deeper, along with links to supplementary resources.

Standardisation, a statistical technique, is established to consider two main factors:
1. The quantity of questions and time limit on a test can differ. For example, a Verbal Reasoning test might have 80 questions with a 50-minute time limit, while a maths test might consist of 100 questions to be completed in 45 minutes. Merely summing up or averaging the “raw scores” from both tests doesn’t provide an equitable reflection of the results, since it doesn’t account for these variations. Standardisation ensures that the outcome of each test is equally valued, regardless of the number of questions or time allocated.

2. The second factor relates to the age of the students at the time of the 11+ test. Due to the varying dates of birth within the school year, one child could be nearly a year older than another, providing a potential advantage such as an additional year’s worth of vocabulary. Considering children gain over 1,000 words per year, this could greatly affect 11+ test results. To alleviate this disadvantage, the scores are adjusted, ensuring a “standard” that applies to all children, no matter their age.

If the oldest and youngest test-takers achieve the same “raw score”, the final 11+ score for the youngest child would be higher, thanks to standardisation. This process gives the younger child additional points to account for their younger age. For example, if both students scored 75/80, the older child’s standardised score could be roughly 133, while the younger child’s might be around 136. These figures are hypothetical and do not reflect actual scores.

There exist a couple of misconceptions about the standardisation process. Firstly, it’s not true that older children have their marks reduced because of their age. Also, it’s a fallacy that boys’ 11+ scores are standardised differently from girls’ scores due to differing development rates. This is not only incorrect but would also contravene the Sex Discrimination Act.

The question arises, how does a raw score of 75/80 transform into 133 or 136? The methods vary, but there are two primary factors used in standardisation. Firstly, the entity responsible for the test design and grading may utilise statistical data regarding the paper’s difficulty level, based on a representative sample from the nation or 11+ area. The second factor considered is the age of all the test-takers.

From this data, an average score is deduced, typically about 100 (though it may reach as high as 111 in certain areas). The lowest score is generally around 69 or 70, and the highest is often limited to 140 or 141. This “maximum score” serves as a threshold rather than the absolute highest score achievable. Although it’s possible to score above 141, the reliability of such scores decreases significantly beyond this point, hence the need for a cut-off.

In regions where school admissions are based on score rankings, the cut-off point isn’t always applied, leading to reported scores over 141. However, such exceptionally high scores are mostly irrelevant due to their rarity, and most school placements are still awarded to children scoring below the usual 141 cut-off. These scores are still recorded, though, to ensure appropriate place allocation if a situation arises where more children scored above 141 than there are available spaces.

In summary, standardisation helps remove inconsistencies in test scores, enabling equal comparisons among children. Nonetheless, the process is often misunderstood due to various unknown elements, such as the test’s relative difficulty and the ability level of the test-taking group, making it impossible for the public to directly calculate a standardised score from a raw score.

This website’s regional pages contain information about previous “minimum standardised scores” (pass marks or qualifying marks) necessary for school admissions in your area. Our 11+ Forum also provides information about the estimated raw scores needed to meet the minimum standardised score in many areas. This information should give you an idea of whether your child is likely to qualify in the 11+.