Quality check: are your assessments giving you the best data?

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Schools need to be able to trust that the assessment data they have is reliable and robust. But how can you tell? In this blog post we will look at standardisation, how to spot good quality data and how to make the most of your school’s assessment data.

What is standardisation and why is it important?

Standardisation plays a crucial role in assessment and education. Standardised tests establish a level ground for assessment - they are fair, valid, reliable and objective meaning schools can have confidence in the results. They serve as valuable tools for evaluating student performance and potential. Standardisation is important because it provides:

  • A baseline for comparison - if schools can measure students against a universal standard, it is easier to evaluate and score their performance
  • An objective measurement - standardised tests are fair and consistent across all schools and do not rely on teachers’ subjective marking
  • Data to support learning - teachers can identify knowledge gaps and tailor their teaching strategies based on students’ test scores.
  • The ability to demonstrate student progress - over time, standardised tests show student improvement by comparing scores year-on-year. This is known as longitudinal data.

Standardised assessments allow schools to benchmark and evaluate students’ performance against the representative sample used during standardisation.

Want to find out more about standardisation?

Click here to read our previous blog post, Standardised Tests 101

Not all assessment data is equal - how to spot the best quality data

Strong standarisation is crucial, and at Cambridge CEM we use the largest data sets to ensure high quality standardisation. Updated every year, our Pre- and Post-16 assessments - MidYIS, Yellis and Alis – have the best standardisation of any baseline and cognitive abilities assessment provider.

MidYIS and Yellis are standardised using over 650,000 student assessments from over 9,500 school cohorts from a period of six academic years. Alis is standardised using over 240,000 student assessments from over 2,600 cohorts from a period of six academic years.

Using data over a longer period means we can follow long-term trends to get a more accurate standardisation but avoid short term fluctuations.

Assessment Provider


Cambridge CEM

MidYIS and Yellis: over 650,000 student assessments from over 9,500 school cohorts

Alis: over 240,000 student assessments from over 2,600 cohorts

GL Assessment

CAT4: 25,000 students [1]

NGRT: 11,700 students [2]

Hodder Education

PUMA and PiRA: over 3,500 students [3]

Alps Education

No data available


To make the results as nationally-representative as possible, we control for the type of school (state selective, state non-selective and independent) and we make a correction for the exam attainment of the schools. The sample consists of students in mainstream English schools.

To make sure that our standardised scores are meaningful, we have a clearly defined target population that we standardise against. For example, for MidYIS and Yellis we provide nationally standardised scores, with the target population being all students in mainstream Secondary schools.

Meaningful and accurate scores - how are other schools using assessment data?

“CEM data gives us an external, impartial baseline with a large database. CEM assessments are an ideal tool – we use them for lots of different purposes." - Cairo English School

Making the most of the data: how can high quality standardisation benefit your school?

Evidence-based decision-making is essential for schools and they need to be able to trust that the data they have is reliable and robust. Here are some examples of where strong assessment data quality is important:

Evidence for accountability and transparency:

When reporting to governors or engaging in conversations with parents, you have to present evidence that withstands scrutiny. Reliable data serves as the foundation of accountability. Similarly, transparent reporting relies on data quality, assuring you that your decisions are led by accurate information.

Strategic insights for improvement:

School improvement strategies demand precision. Data informs these strategies, enabling you, as school leaders, to identify areas for growth, allocate resources effectively, and tailor interventions. High-quality data guides schools toward evidence-based improvements.

Optimising teaching and learning:

Student success rests on effective teaching and learning. Your teachers rely on data to personalise instruction, track progress, and address individual needs. Quality data ensures that teaching decisions are well-informed. It empowers teachers to adapt pedagogical approaches, recognise patterns, and intervene proactively.

Confidence in decision-making:

Decisions - whether curricular, resource allocation, or policy-related - shape the educational experience. Having the best quality assessment data instils confidence in those decisions, allowing school leaders to make informed choices, based on a solid foundation.


[1] https://www.gl-assessment.co.uk/assessments/cat4/

[2] https://www.gl-assessment.co.uk/assessments/new-group-reading-test/

[3] https://www.risingstars-uk.com/media/Rising-Stars/Assessment/PUMA-KS3-Brochure.pdf and https://www.risingstars-uk.com/media/Rising-Stars/Assessment/PiRA-KS3-Brochure.pdf