AQA A-level COMPUTER SCIENCE Paper 2 QP 2021
A-level
COMPUTER SCIENCE
7517/2
Paper 2
Mark scheme
June 2021
Version: Final 1.1
*216A7517/2/MS*
, MARK SCHEME – A-LEVEL COMPUTER SCIENCE – 7517/2 – JUNE
2021
Mark schemes are prepared by the Lead Assessment Writer and considered, together with
the relevant questions, by a panel of subject teachers. This mark scheme includes any
amendments made at the standardisation events which all associates participate in and is
the scheme which was used by them in this examination. The standardisation process
ensures that the mark scheme covers the students’ responses to questions and that every
associate understands and applies it in the same correct way.
As preparation for standardisation each associate analyses a number of students’ scripts.
Alternative answers not already covered by the mark scheme are discussed and legislated for.
If, after the standardisation process, associates encounter unusual answers which have not
been raised they are required to refer these to the Lead Examiner.
It must be stressed that a mark scheme is a working document, in many cases further
developed and expanded on the basis of students’ reactions to a particular paper.
Assumptions about future mark schemes on the basis of one year’s document should be
avoided; whilst the guiding principles of assessment remain constant, details will change,
depending on the content of a particular examination paper.
Further copies of this mark scheme are available from aqa.org.uk
2
, MARK SCHEME – A-LEVEL COMPUTER SCIENCE – 7517/2 – JUNE
2021
Level of response marking instructions
Level of response mark schemes are broken down into levels, each of which has a descriptor.
The descriptor for the level shows the average performance for the level. There are marks in
each level.
Before you apply the mark scheme to a student’s answer read through the answer and
annotate it (as instructed) to show the qualities that are being looked for. You can then
apply the mark scheme.
Step 1 Determine a level
Start at the lowest level of the mark scheme and use it as a ladder to see whether the
answer meets the descriptor for that level. The descriptor for the level indicates the
different qualities that might be seen in the student’s answer for that level. If it meets the
lowest level then go to the next one and decide if it meets this level, and so on, until you
have a match between the level descriptor and the answer. With practice and familiarity
you will find that for better answers you will be able to quickly skip through the lower levels
of the mark scheme.
When assigning a level you should look at the overall quality of the answer and not look to
pick holes in small and specific parts of the answer where the student has not performed
quite as well as the rest. If the answer covers different aspects of different levels of the
mark scheme you should use a best fit approach for defining the level and then use the
variability of the response to help decide the mark within the level, ie if the response is
predominantly level 3 with a small amount of level 4 material it would be placed in level 3
but be awarded a mark near the top of the level because of the level 4 content.
Step 2 Determine a mark
Once you have assigned a level you need to decide on the mark. The descriptors on how to
allocate marks can help with this. The exemplar materials used during standardisation will
help. There will be an answer in the standardising materials which will correspond with
each level of the mark scheme. This answer will have been awarded a mark by the Lead
Examiner. You can compare the student’s answer with the example to determine if it is the
same standard, better or worse than the example. You can then use this to allocate a mark
for the answer based on the Lead Examiner’s mark on the example.
You may well need to read back through the answer as you apply the mark scheme to
clarify points and assure yourself that the level and the mark are appropriate.
Indicative content in the mark scheme is provided as a guide for examiners. It is not
intended to be exhaustive and you must credit other valid points. Students do not have to
cover all of the points mentioned in the Indicative content to reach the highest level of the
mark scheme.
An answer which contains nothing of relevance to the question must be awarded no marks.
3
, MARK SCHEME – A-LEVEL COMPUTER SCIENCE – 7517/2 – JUNE
2021
A-level Computer Science
Paper 2
June 2021
To Examiners:
When to award '0' (zero) when inputting marks on CMI+
A mark of 0 should be awarded where a candidate has attempted a question but
failed to write anything credit worthy.
Insert a hyphen when a candidate has not attempted a question, so that
eventually the Principal Examiner will be able to distinguish between the
two (not attempted / nothing credit worthy) in any statistics.
This mark scheme contains the correct responses which we believe that
candidates are most likely to give. Other valid responses are possible to some
questions and should be credited. Examiners should refer responses that are
not covered by the mark scheme, but which they deem creditworthy, to a
Team Leader.
The following annotation is used in the mark scheme:
; - means a single mark
// - means alternative response
/ - means an alternative word or sub-phrase
A. - means acceptable creditworthy answer
R. - means reject answer as not creditworthy
NE. - means not enough
I. - means ignore
DPT. - in some questions a specific error made by a candidate, if repeated, could
result in the loss of more than one mark. The DPT label indicates that this
mistake should only result in a candidate losing one mark on the first
occasion that the error is made.
Provided that the answer remains understandable, subsequent marks should
be awarded as if the error was not being repeated.
4
A-level
COMPUTER SCIENCE
7517/2
Paper 2
Mark scheme
June 2021
Version: Final 1.1
*216A7517/2/MS*
, MARK SCHEME – A-LEVEL COMPUTER SCIENCE – 7517/2 – JUNE
2021
Mark schemes are prepared by the Lead Assessment Writer and considered, together with
the relevant questions, by a panel of subject teachers. This mark scheme includes any
amendments made at the standardisation events which all associates participate in and is
the scheme which was used by them in this examination. The standardisation process
ensures that the mark scheme covers the students’ responses to questions and that every
associate understands and applies it in the same correct way.
As preparation for standardisation each associate analyses a number of students’ scripts.
Alternative answers not already covered by the mark scheme are discussed and legislated for.
If, after the standardisation process, associates encounter unusual answers which have not
been raised they are required to refer these to the Lead Examiner.
It must be stressed that a mark scheme is a working document, in many cases further
developed and expanded on the basis of students’ reactions to a particular paper.
Assumptions about future mark schemes on the basis of one year’s document should be
avoided; whilst the guiding principles of assessment remain constant, details will change,
depending on the content of a particular examination paper.
Further copies of this mark scheme are available from aqa.org.uk
2
, MARK SCHEME – A-LEVEL COMPUTER SCIENCE – 7517/2 – JUNE
2021
Level of response marking instructions
Level of response mark schemes are broken down into levels, each of which has a descriptor.
The descriptor for the level shows the average performance for the level. There are marks in
each level.
Before you apply the mark scheme to a student’s answer read through the answer and
annotate it (as instructed) to show the qualities that are being looked for. You can then
apply the mark scheme.
Step 1 Determine a level
Start at the lowest level of the mark scheme and use it as a ladder to see whether the
answer meets the descriptor for that level. The descriptor for the level indicates the
different qualities that might be seen in the student’s answer for that level. If it meets the
lowest level then go to the next one and decide if it meets this level, and so on, until you
have a match between the level descriptor and the answer. With practice and familiarity
you will find that for better answers you will be able to quickly skip through the lower levels
of the mark scheme.
When assigning a level you should look at the overall quality of the answer and not look to
pick holes in small and specific parts of the answer where the student has not performed
quite as well as the rest. If the answer covers different aspects of different levels of the
mark scheme you should use a best fit approach for defining the level and then use the
variability of the response to help decide the mark within the level, ie if the response is
predominantly level 3 with a small amount of level 4 material it would be placed in level 3
but be awarded a mark near the top of the level because of the level 4 content.
Step 2 Determine a mark
Once you have assigned a level you need to decide on the mark. The descriptors on how to
allocate marks can help with this. The exemplar materials used during standardisation will
help. There will be an answer in the standardising materials which will correspond with
each level of the mark scheme. This answer will have been awarded a mark by the Lead
Examiner. You can compare the student’s answer with the example to determine if it is the
same standard, better or worse than the example. You can then use this to allocate a mark
for the answer based on the Lead Examiner’s mark on the example.
You may well need to read back through the answer as you apply the mark scheme to
clarify points and assure yourself that the level and the mark are appropriate.
Indicative content in the mark scheme is provided as a guide for examiners. It is not
intended to be exhaustive and you must credit other valid points. Students do not have to
cover all of the points mentioned in the Indicative content to reach the highest level of the
mark scheme.
An answer which contains nothing of relevance to the question must be awarded no marks.
3
, MARK SCHEME – A-LEVEL COMPUTER SCIENCE – 7517/2 – JUNE
2021
A-level Computer Science
Paper 2
June 2021
To Examiners:
When to award '0' (zero) when inputting marks on CMI+
A mark of 0 should be awarded where a candidate has attempted a question but
failed to write anything credit worthy.
Insert a hyphen when a candidate has not attempted a question, so that
eventually the Principal Examiner will be able to distinguish between the
two (not attempted / nothing credit worthy) in any statistics.
This mark scheme contains the correct responses which we believe that
candidates are most likely to give. Other valid responses are possible to some
questions and should be credited. Examiners should refer responses that are
not covered by the mark scheme, but which they deem creditworthy, to a
Team Leader.
The following annotation is used in the mark scheme:
; - means a single mark
// - means alternative response
/ - means an alternative word or sub-phrase
A. - means acceptable creditworthy answer
R. - means reject answer as not creditworthy
NE. - means not enough
I. - means ignore
DPT. - in some questions a specific error made by a candidate, if repeated, could
result in the loss of more than one mark. The DPT label indicates that this
mistake should only result in a candidate losing one mark on the first
occasion that the error is made.
Provided that the answer remains understandable, subsequent marks should
be awarded as if the error was not being repeated.
4
