Quick data guide
What data is available?
YARC provides three different types of normative scores:
- standard scores
- percentile ranks
- age-equivalent scores
We would urge teachers using YARC to rely on standard scores rather than age-equivalent scores or percentile ranks for interpreting and expressing the scores obtained on the test.
Standard scores
For most purposes, standard scores are the best way of expressing a pupil’s performance on tests of ability. They express a child’s score in relation to the spread of scores obtained by a sample of children of the same age. Here’s a guide to interpreting standard scores:
|
Score |
Meaning |
|
70-79 (or below) |
a pupil with a severe reading problem |
|
around 85 |
a pupil with a moderate degree of reading difficulty |
|
around 100 |
a pupil whose reading is at an average level for their age |
|
around 115 |
a pupil who can be considered a good reader |
|
around 125 (or above) |
a pupil who can be considered an excellent reader |
Percentile ranks
A percentile rank gives the pupil’s ranking in relation to other pupils of the same age. A percentile rank of 50 means the pupil has performed as well as or better than 50% of children of the same age i.e., a percentile rank of 50 is the average score for the child’s age.
However, percentiles only express a child’s relative standing and, owing to their mathematical properties, these scores cannot be meaningfully combined or averaged.
Age-equivalent scores
Also known as ‘reading ages’, age-equivalent scores are ages at which a given ‘ability score’ is the average. For each component of YARC Early Reading, a pupil’s test raw score is converted to an ability score. The ability score expresses a pupil’s ability on an arbitrary scale of measurement. These ability scores can then be expressed in terms of the average age at which such a score was obtained in the standardisation sample.
However, age-equivalent scores do not contain any information about the spread of scores on a test at a particular age. Given that pupils whose scores need to be compared will often differ in age, age-equivalent scores become very cumbersome to interpret.