Overview

This article explains how the DfE's EBacc Value Added (VA) measure is calculated. The information in this article is useful for troubleshooting or to gain an insight into how the calculations in Sisra Analytics work.

Calculations video

Calculations

Student VA Element Score

The formula to calculate KS4 EBacc Value Added (VA) for a student is as follows:

Student VA Element Score  = Actual Score – Estimated Score^*

_{* This is broken down to more detail in the worked example below.}

Whole School VA Element Score

The formula to calculate whole school value added is as follows:

Whole School VA Element Score  = Total VA Element Score ÷ Number of students included^*

_{* Also known as Coverage, this is the number of students with a KS2 APS above zero and entered for that EBacc element.}

Worked example

• To calculate a student’s VA score in each element, their KS2 prior attainment must be calculated first. This is the average of your students’ official core KS2 Levels for that reporting year.

  For example, Student A achieved a Scaled Score of 90 in KS2 English Reading and 85 in KS2 Maths. Their KS2 Prior Attainment is:

  Student A's KS2 Prior Attainment  = (90 + 85) ÷ 2= 87.5

• Next determine the Grade Points for Science, Humanities, and Languages:

  1. Humanities and Languages - This is the points from the student’s highest-scoring EBacc Humanities or Language Grade. For example, if a student achieves a 5 in Geography and a 6 in History, the grade 6 for History would count for Humanities.
  2. Science - This is calculated using the 2 points counting towards the Science element. The points for the two sciences are averaged to give the Science element. For example, a student with a Combined Science grade of 6-5 has an average of 5.5 points.

  Student A has the following grade points for each element:

  1. Science - 6
  2. Humanities - 4
  3. Languages - 4
     
     

• After determining the Grade Points for Science, Humanities, and Languages, find the students VA estimates based on their KS2 prior attainment. The following examples are calculated using the latest 2024 estimates from the DfE.

  For example, Student A has a KS2 prior attainment of 87.5. According to the table below, this would give a VA Estimate of 2.01 for Science, 1.70 for Humanities, and 3.22 for Languages:

  KS2 prior attainment group	KS2 average scaled score range	Science average	Humanities average	Languages average
  1	59 to 82	1.83	1.72	4.36
  2	82.5 to 86	1.78	1.50	3.22
  3	86.5 to 87.5	2.01	1.70	3.22
  4	88 to 89	2.15	1.84	3.31

• After completing Steps 1 - 3, the student’s Value Added Scores for each element can then be calculated:

  Student A's Value Added Scores
  	Actual Score (a)	Estimated Score (b)	VA Score (a - b)
  Science VA	6	2.01	6 - 2.01 = 3.99
  Language VA	4	3.22	4 - 3.22 = 0.78
  Humanities VA	4	1.70	4 - 1.70 = 2.30

• Add up the VA Scores of all students in each element:

  Student Name	Science VA	Language VA	Humanities VA
  Student 1	3.99	0.78	2.03
  Student 2	0.94	1.74	-
  ...	...	...	...
  Student 208	4.63	-	2.67
  Total	539.14	303.54	460.53

  In the example above, the total VA Scores are as follows: 539.14 for Science, 303.54 for Languages, and 460.53 for Humanities. This figure is then divided by the number of students included.

• Next, determine the Coverage. This is the number of students included in each VA element (Science, Languages, and Humanities). For each element, count the number of students with a KS2 APS above zero that have been entered for that EBacc element.

  For example, there are 208 students in the cohort. All students have a KS2 APS above zero. However, only 120 of these students have an entry in an EBacc eligible Language qualification. Similarly, all students are entered for Science and only 139 for Humanities.

• The Whole School VA is calculated by dividing the Total VA Score by the Coverage:

  	Total VA Score (d)	Coverage (e)	Whole School Value Added Score (d ÷ e)
  Science VA	539.14	208	539.14 ÷ 208 = 2.592
  Language VA	303.54	120	303.54 ÷ 120 = 2.530
  Humanities VA	460.53	139	460.53 ÷ 139 = 3.313

• A Value Added Score can be used to calculate a 95% Confidence Interval. This can be used when the VA Score is not fully reflective for a variety of different reasons, for example if a student was absent for their exam. The confidence interval will provide you with a range of values ensuring that, statistically, you can be 95% confident the schools true VA Score lies.

  The calculation for Confidence Intervals is very similar to the Progress 8 Confidence Interval calculation, however you’d use VA standard deviations, as shown below. This is calculated for each VA Element (Science, Humanities, and Languages) for the school:

  VA Confidence Interval = 1.96 x National VA Standard Deviation^* ÷ (√Cohort Size)

  _{* The standard deviation of each VA element nationally is provided for the DfE each year.}

  The upper / lower confidence limits of this confidence interval is given by the formula:

  [LowCI_s, UppCI_s] = [VA_s - CI_s, VA_s + CI_s]

  Where:

  LowCIs	The lower confidence limit for the School’s Value Added Score
  UppCIs	The upper confidence limit for the School’s Value Added Score
  VAs	The School’s Value Added Score
  CIs	The size of the confidence interval for the School’s Value Added Score

  The size of the Confidence Interval for the School’s Value Added Score (CI_s) is calculated as follows:

  CI_s = 1.96 × (σ_N ÷ √n_s)

  Where:

  1.96	The critical value for a 95% confidence interval
  σN	The standard deviation of the Value Added Scores for all eligible pupils nationally
  ns	The number of eligible pupils that belong to the school

  This gives the VA Upper and Lower Confidence Intervals as follows:

  Lower Confidence Interval = School VA Score (for element) – Confidence Interval

  Upper Confidence Interval = School VA Score (for element) + Confidence Interval

  For example, using these formulae, the following Confidence Intervals are calculated:

  Whole School Confidence Intervals (VA)
  Science Confidence Interval	1.96 x (1.374653 ÷ (√208)) = 0.187
  Language Confidence Interval	1.96 x (1.810855 ÷ (√120)) = 0.324
  Humanities Confidence Interval	1.96 x (1.721711 ÷ (√139)) = 0.286

  This would then give the following Confidence Limits:

  Whole School Upper / Lower Confidence Intervals (VA)
  	Lower	Upper
  Science	2.592 - 0.187 = 2.405	2.592 + 0.187 = 2.779
  Languages	2.530 - 0.324 = 2.206	2.530 + 0.324 = 2.854
  Humanities	3.313 - 0.286 = 3.027	3.313 + 0.286 = 3.599

Related information

• Sisra Analytics: KS3/4 - What is Value Added (VA)?

Updated 28 October 2025 16:19