AW-is a note to the examiner to indicate that it cannot be expected that a candidate will use words exactly like those in the mark scheme. AW therefore means 'accept A(alternative) W(wording) - so long as the meaning is the same as the phrase used in the mark scheme.
R-is quite simply 'Reject'. I would be used, for example, in a question on respiration where there might be a mark for RELEASE of energy. After the word 'release', there may be ( R production)
OVP-is a short-hand we don't like to use any more than we can help. It means that the examiner may award a mark for an 'O(ther) V(alid) P(oint)'.
M-Method mark, awarded for a valid method applied to the problem. Method marks
are not lost for numerical errors, algebraic slips or errors in units. However, it is
not usually sufficient for a candidate just to indicate an intention of using some
method or just to quote a formula; the formula or idea must be applied to the
specific problem in hand, e.g. by substituting the relevant quantities into the
formula. Correct application of a formula without the formula being quoted
obviously earns the M mark and in some cases an M mark can be implied from a
correct answer.
A-Accuracy mark, awarded for a correct answer or intermediate step correctly
obtained. Accuracy marks cannot be given unless the associated method mark is
earned (or implied).
B-Mark for a correct result or statement independent of method marks.
• When a part of a question has two or more "method" steps, the M marks are generally
independent unless the scheme specifically says otherwise; and similarly when there
are several B marks allocated. The notation DM or DB (or dep*) is used to indicate that
a particular M or B mark is dependent on an earlier M or B (asterisked) mark in the
scheme. When two or more steps are run together by the candidate, the earlier marks
are implied and full credit is given.
• The symbol ? implies that the A or B mark indicated is allowed for work correctly
following on from previously incorrect results. Otherwise, A or B marks are given for
correct work only. A and B marks are not given for fortuitously "correct" answers or
results obtained from incorrect working.
• Note: B2 or A2 means that the candidate can earn 2 or 0.
B2/1/0 means that the candidate can earn anything from 0 to 2.
The following abbreviations may be used in a mark scheme or used on the scripts:
AG-Answer Given on the question paper (so extra checking is needed to ensure
that the detailed working leading to the result is valid)
BOD-Benefit of Doubt (allowed when the validity of a solution may not be
absolutely clear)
CAO-Correct Answer Only (emphasising that no "follow through" from a previous
error is allowed)
CWO-Correct Working Only – often written by a ‘fortuitous' answer
ISW-Ignore Subsequent Working
MR-Misread
PA-Premature Approximation (resulting in basically correct work that is
insufficiently accurate)
SOS-See Other Solution (the candidate makes a better attempt at the same
question)
I hope that answers your question. If not, I shall be here for several more days !
