How do we calculate a mark if a student missed one of their A Level or GCSE exams?

How does it work?

We calculate a mark for the exam or assessment (unit) you missed based on:

• your marks in the other exams or assessments (units) you completed for your subject
• your performance in your exams or assessments (units) compared to the performance of all other students.

To calculate a mark for the exam or assessment (unit) you missed, we calculate three statistics:

• the average mark (the mean) for each unit based on the marks of all the students for that unit.
• a measure of spread (the standard deviation) for each unit based on the marks of all the students for that unit.
• a z-score that tells us how far from the average (mean) score for each unit you have achieved.

To calculate a z-score we use the following formula:

To give you an idea of how this works, here’s some examples:

Example 1

Abi is taking an A Level subject with three examined units. She was able to complete the examined units 1 and 2 but she missed her unit 3 exam.  All three unit exams are weighted equally and have a maximum of 80 marks.

Step 1: Calculate the z-scores for the completed units

Unit 1: Abi got a mark of 62 out of a maximum of 80 marks.

The average (mean) unit mark for unit 1 = 50

The standard deviation for unit 1 = 10

Abi’s z-score for unit 1 is (62-50) ÷ 10 = 1.2

Note: Abi has a positive z-score for unit 1 because her actual mark is above the average (mean) for unit 1.

Unit 2: Abi got a mark of 58 out of a maximum of 80 marks.

The average (mean) unit mark for unit 2 = 60

The standard deviation for unit 2 = 5

Abi’s z-score for unit 2 is  (58-60) ÷ 5 = -0.4

Note: Abi has a negative z-score for unit 2 because her actual mark is below the average (mean) for unit 2.

Step 2: Calculate the z score for unit 3 (the missed unit)

To calculate Abi’s z-score for unit 3 (the missed unit), the average of her two z-scores for unit 1 and unit 2 is calculated

z-score (unit 3) = (1.2 + -0.4) ÷ 2 = 0.4
                               

Step 3: Calculate the mark for unit 3 (the missed unit)

To calculate the mark for unit 3 (the missed unit), the z-score for unit 3 (Step 2) is combined with the average (mean) and standard deviation for unit 3, as follows

The average (mean) unit mark for unit 3 = 55

The standard deviation for unit 3 = 8

Calculated mark = average (mean) + (z-score x standard deviation)

Calculated mark = 55 + (0.4 x 8)

                            = 58.2

                            = 58 (rounded to the nearest whole mark)

Note: Abi has a calculated mark that is above the average (mean) for unit 3 because her calculated z-score (Step 2) is positive.

Summary

Example 2

Jack is taking a GCSE subject with two examined units. He was able to complete the examined unit 1 but he missed his unit 2 exam.  Both his two unit exams are weighted equally and have a maximum of 80 marks.

Step 1: Calculate the z-score for unit 1 (the completed unit)

Unit 1: Jack got a mark of 62 out of a maximum of 80 marks.

The average (mean) unit mark for unit 1 = 50

The standard deviation for unit 1 = 10

Jack’s z-score for unit 1 is  (62-50) ÷ 10 = 1.2

Note: Jack has a positive z-score for unit 1 because his actual mark is above the average (mean) for unit 1.

Step 2: Calculate the mark for unit 2 (the missed unit)

To calculate the mark for unit 2 (the missed unit), Jack is given the same z-score for unit 2 (the missed unit) as calculated for unit 1 (the completed unit)

i.e. Jack’s z-score for unit 2 (the missed unit) = 1.2

The average (mean) unit mark for unit 2 = 55

The standard deviation for unit 2 = 8

Calculated mark = average (mean) + (z-score x standard deviation)

Calculated mark = 55 + (1.2 x 8)

                            = 64.6

                            = 65 (rounded to the nearest whole mark)

Note: Jack has a calculated mark that is above the average (mean) for unit 2 because his z-score (Step 1) is positive.

Summary

More information

Your school or college exams officer applies on your behalf about this process so do speak to them in the first instance.

Find more information on the JCQ website:

• FAQs – providing qualification grades when exams are missed for acceptable reasons
• Estimating the mark when a candidate is absent from an examination