Demystifying standardised scores

Published on: 03 May 2018

“The power of using standardised scores in assessments is phenomenal. Standardised scores make assessment processes purposeful and meaningful, and they should be seen as your new best friend, not something that should be feared.”

Demystifying standardised scores

By Mark Loveday, Assistant Headteacher and Head of School Support and Outreach Services, Chadsgrove Teaching School Alliance

So you’ve bought the assessments and planned how to deliver them, but what are the results going to show you and what does it mean?

In my experience, the use of standardised scores has often baffled SENCos and school leaders. They provide great baseline data but what do they actually show?

When test scores are taken from a large enough sample group they fit into a pattern known as ‘normal distribution’. Normal distribution allows for comparisons to be made across standardised assessments.

To be able to collate a normal distribution of results, test developers have to develop, trial and standardise the assessment before conversion of the results to a standard scale (standardised score) can occur. To achieve this, tests have to be standardised against a sufficiently large and representative reference group (GL Assessment’s Progress Test Series was standardised on 90,000 pupils, for example). Basically, they have to ensure that they have trialled the test with sufficient numbers of people to ensure accurate standardisation. That means they’ve done the hard work and we, as teachers, have a super comparison tool!

In a snapshot, standardised scores allow you to compare an individual’s result with that of the reference group (normed sample). This in turn allows you to ascertain whether the pupil is average, below average or above average when compared to the results from the student population in the UK. The great thing about standardised scores is they provide a ‘common scale’ across standardised assessments and allow for comparisons to be made between differing assessment areas.

How does this work, I hear you say? Well, let’s look at an example for a child who we will call Boris.

Boris has completed the Progress Test in English and Progress Test in Maths, and the results show that Boris has achieved a standard score of 73 in English and 97 in Maths. This allows us to say that Boris has achieved a below average score in English, but an average score in Maths.

Further assessment into Boris’s attainment in English could then be completed using further diagnostic assessments to find out more (such as the York Assessment of Reading for Comprehension or the Phonological Assessment Battery ), as required. Because all of these scores are standardised they allow us to make a direct comparison between the different tests, allowing for an individual pupil profile of strengths and difficulties to be created. Without these, we would have had a series of test scores that individually highlight areas of strengths and difficulties, but we would not be able to effectively make direct comparisons.

The power of using standardised scores in assessments is phenomenal. They can track cohorts, identify individuals who may need support, assess progress in interventions and much more! Standardised scores make assessment processes purposeful and meaningful, and they should be seen as your new best friend, not something that should be feared.

To find out more about standardised assessments, download our new free guide.