Our added value

Value-added at St Mary's

Year-on-year, our value-added scores highlight our impressive track record of ‘adding value’ to our academic achievements – by quantifying the additional progress each girl makes due to the quality of teaching and learning at St Mary’s.

Whilst we are a selective independent school, each cohort at St Mary’s typically represents a wide ability range. Our approach is very much about ensuring every girl – whatever her abilities and interests – reaches her full potential.

We have a proud track record at both GCSE and A Level, however, exam grades alone cannot show the mammoth steps some students make to attain their personal summits. As our inspection by the Independent Schools Inspectorate (ISI) confirmed, we offer the: “highest quality of learning … supported by … outstanding additional support for pupils who need it, and by excellent teaching.”

The national Value-added Programme, run by Durham University Centre of Evalution and Monitoring (CEM), enables us to measure the impact of our support and teaching, on the learning journey of every single girl.

Our Value-added scores, calculated by CEM, quantify the additional progress each student makes due to the quality of teaching and learning at St Mary’s.

Our value-added

Over an 8 year period, our value-added scores average at (0.65) at GCSE, per girl, per subject. To put this in context, this could be the difference between 10 grade 8s and 10 grade 9s. This is important, as it enables us to open up more future paths, at A Level, university and beyond across the ability range.

What is the purpose of value-added?

CEM at Durham University describe value-added as a measure, which offers:

  • a fairer indication of how far a student has come
  • a fairer measure of how well the school has brought that student on
  • a fairer way to make comparisons between different schools’ performances

Value-added highlights to role of quality of teaching, availability of resources and many other factors, that may have an effect on the progress of individual pupils. It is calculated by considering a fixed period of time, to measure the amount of improvement a school has added to the pupil.

All schools improve their pupils in this way. However, if one school is increasing the achievement level of its pupils more than other schools are, then its pupils gain an additional advantage. It is this relative advantage that CEM refer to as 'value-added'.

How is value-added calculated?

In Year 10, students undertake a computer-based YELLIS assessment, provided by CEM at Durham University. This provides us with a detailed picture of each student's academic profile and potential across different subjects.

Using this data CEM predicts GCSE grades for each girl, by comparing with past students of similar academic profiles. When students collect their GCSE results at the end of Year 11, we compare the actual results with the grades predicted by CEM. This allows us to evaluate how much 'added-value' our teaching and wider education has delivered over the two-year period.

The process is the same for A Level students, with a baseline CEM assessment taken at the start of Year 12.

A whole host of factors influence academic attainment. From changing grade boundaries, to students' effort levels, personal health, home lives and availability of support. CEM takes these wider factors into account and in 2016, CEM indicated that a value-added score of more than 0.2 could be attributed directly to a schools' teaching and resources.

Our value-added scores 2019
  • Top 28% of schools nationally at A Level

Durham University CEM

Value-added at the Centre for Evaluation and Monitoring

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Our view ...

"We take enormous pride in offering places to students of a wider ability range than other local independent schools. We have the freedom and resources to invest in each and every student - including a rigorous academic environment, tailored support and our in-depth pastoral care programme. This approach adds value, making a positive difference to our students' academic accomplishments"
Charlotte Avery, Headmistress