Secondary School Performance Tables 2003

VALUE ADDED TECHNICAL INFORMATION

Introduction

This annex describes the method that has been used to calculate the KS3 to GCSE/GNVQ value added measure.

The annex explains the calculation of the KS3 to GCSE/GNVQ value added measure and includes details of how each school's value added measure has been calculated.

It also describes the calculation of the school's capped average point score and the contextual information shown with the value added measure.

Key Stage 3 to GCSE/GNVQ value added measure

Students included

The KS3 to GCSE/GNVQ value added measure is based on the results achieved by students:

• who were 15 years old on 31 August 2002; and
• were on the school roll on 16 January 2003; and
• for whom we were able to match prior attainment in KS3 tests.

All students for whom all results are disregarded at KS3 will be excluded from the value added calculations, with one exception: if a student was disapplied in all 3 subjects or had a combination of disapplied and disregarded results at KS3 and achieved at least one GCSE/GNVQ at grade A*-G, then he/she will be included in the calculation with an input score of zero.

Allocation of points: GCSE/GNVQ results

GNVQ: Equivalence to GCSE and allocation of points

Point scores for KS3 results

* E has been discontinued from 2003 and is available for Key Stage 3 prior attainment only.

Input measure (Key Stage 3)

The input measure for each student is calculated as the average point score achieved in the English, mathematics and science KS3 test results. For example, the average point score for a student achieving test levels 4, 4 and 5 in English, mathematics and science respectively would be:

( 27 + 27 + 33 ) / 3 = 29

If any KS3 results for a student are disregarded, the output measure is calculated as the average of the remaining one or two results.

Output measure (GCSE/GNVQ)

The output measure for each student is capped at a student's best eight GCSEs/GNVQs.

Calculation of capped GCSE/GNVQ point score

In order to calculate the capped GCSE/GNVQ point score for each student, each qualification has been divided into records to show its equivalence to the smallest qualification, which is a GCSE (Short Course) and has half the weight of a full GCSE as shown below:

The point score allocated to each result is also divided by the number of records. For example, a student who achieved 3 Bs and 3 Cs at GCSE, an A* for a GCSE (Short Course) and a full Intermediate GNVQ with distinction would have their results broken down and their capped GCSE/GNVQ point score calculated in the following way:

Only the 16 highest scoring records (i.e. the best 8 GCSEs/GNVQs) are used to calculate a student's point score. In this case the lowest five records worth 2.5 points each and representative of two and a half GCSEs at grade C are disregarded. In this example the student's point score is 54.50.

The average capped point score per student for a school is calculated by dividing the overall number of points (capped as described above) by the number of students.

Calculation of a student's value added score

The student's value added score is based on comparing their GCSE/GNVQ performance with the median GCSE/GNVQ performance of other students with the same or similar prior attainment at Key Stage 3. The median value is the middle value - with half of the students having a capped GCSE/GNVQ point score at or below the median, and half at or above.

The graphs below give the pattern of median capped GCSE/GNVQ point scores across the range of Key Stage 3 point scores nationally - joining the medians gives the `national median line'. There are two graphs: one shows median scores for mainstream schools and the other shows median scores for students in special schools only.

The national Key Stage 3 to GCSE/GNVQ median scores are shown in the tables below. Table A lists median scores for students in mainstream schools and Table B lists median scores for students in special schools.

Table A: Mainstream schools

Table B: Special schools

Calculation and presentation of a school's value added (Key Stage 3 to GCSE/GNVQ)

In the following example, school B has four students eligible for inclusion in the calculation with KS3 and GCSE/GNVQ average point scores. The median average point scores have been allocated according to the national median line for mainstream schools shown above and a value added score calculated for each student.

A school's value added score is a simple average (arithmetic mean) of the value added measures for all the students in the school. For example, for a mainstream school:

The value added score for each school has been published in terms of a measure based around 100 - i.e. by adding 100 to the school's value added score. In the example above, the value added score for school B would be shown as:

The coverage indicator

This shows, as a percentage, the proportion of students included in the KS3 to GCSE/GNVQ value added calculation. For example, if a school had 10 students aged 15 on roll but only 6 of them were included in the value added measure, then the actual number of students included in the value added score would be 6. The coverage indicator in this example would be:

( 6 / 10 ) * 100 = 60%

A value added measure has not been published for schools with less than 50% coverage.

Average number of GCSEs/GNVQs taken by students in the value added calculation

This shows the average number of GCSEs/GNVQs taken by each student included in the value added calculation. It has been calculated by dividing the total number of GCSE/GNVQ examinations taken by each student by the number of students included in the calculation. The total number of examinations has been determined using the table of GCSE and GNVQ equivalencies set out in the first part of this annex.

For example, a school has ten students who are included in the calculation and the number of GCSEs/GNVQs taken by each of the students is as follows:

The calculation in this example for the average number of GCSEs/GNVQs taken by students would be:

( 8 + 9 + 10 + 6 + 8 + 8.5 + 8 + 10 + 9.5 + 4.5 ) / 10 = 8.15

This would be rounded to 8.2 using normal rounding conventions.

The stability indicator

This shows the percentage of students included in the value added calculation who took both their KS3 tests and GCSEs/GNVQs in the same school. For example, if a school has 10 students in the value added calculation and only 7 took both their KS3 tests and GCSE/GNVQ examinations in the same school, then the stability indicator would be:

( 7 / 10 ) * 100 = 70%