Published 23 Dec 2016 • 20 mins read
Marking, grading and giving feedback
This set of materials is intended to provide guidance and support for those who are new to assessing and giving feedback and who are asked to implement an existing assessment process. The emphasis here is to provide practical help in doing the marking you are asked to do, however, there will also be some opportunity to think about assessment more broadly and to critique the approaches we use particularly in UK Higher Education
Marking, grading and giving feedback
This set of materials is intended to provide guidance and support for those who are new to assessing and giving feedback and who are asked to implement an existing assessment process. The emphasis here is to provide practical help in doing the marking you are asked to do, however, there will also be some opportunity to think about assessment more broadly and to critique the approaches we use particularly in UK Higher Education.
This Chapter is provided in six sections:
- Some Key Features of Assessment
- Features of good quality assessment
- Getting Started with Marking
- Assessment Criteria and Marking Schemes
- Providing Useful Feedback
- Two Assessment Challenges
and is completed with a set of Further Reading suggestions and useful web resources.
1. Some Key Features of Assessment
1. i. Why Assess?
Assessment can be used for a number of different educational purposes it can be summative, formative or diagnostic
Summative assessment ‘counts’ and contributes the final grade. It happens after learning has taken place and is used to judge how well a student has learnt.
This is commonly described as Assessment of Learning.
Formative assessment is the feedback we provide, any marks given are effectively indicative and don’t contribute to the final grade. It ideally happens whilst learning is taking place to guide future learning.
This is commonly described as Assessment for Learning.
Diagnostic assessment is a pre-test, to see if the learner has the right background knowledge and skill to take the module or to judge what level of challenge and support they will require. It usually happens before or at the beginning of learning.
Frequently individual assessments have multiple purposes – so a piece of coursework may be conducted during the module in order to provide feedback but also contributes a small percentage towards the final, overall mark – thus combining formative and summative properties.
1. ii. The Importance of Assessment
- High Stakes and Low Stakes Assessment
If you are assessing students in their first year it is likely that the assessment will be relatively low stakes – i.e. the consequences of success and failure may not dramatically affect the student or their progress on the programme in which they are studying. However, assessments later in the programme and particularly in the final year are likely to be of higher stakes with the potential impact on the student being much greater. This could be in terms of their overall achievement on the course or on the course/career choices available to them in the future.
· Student reactions
Whilst the importance of the assessment in terms of marks and consequences is easy to determine within any course structure – the impact of assessment results on individual students is much more unpredictable and difficult to judge. Some learners will respond to a low mark with the determination to do better next time – and it will give them impetus to work harder and improve. Whilst another student will take a poor grade very defensively and may feel that the grade is unfair in someway. Yet another learner will react very personally and perhaps feel that they are not able to improve and let the poor mark badly dint their confidence and motivation.
1. iii. Convergent Assessment or Divergent Assessment
Convergent assessments include questions that have right answers and test the learner’s knowledge of facts and procedures.
Divergent assessments anticipate a range of different responses and rewards academic skills such as analysis, critique and evaluation (Torrence et al., 2001).
Assessment is commonly a mixture of these two – so there may well be parts of the work that you are marking that will have a set of right and wrong answers. There may be elements that the students will clearly win or lose marks because they have or haven’t included these specific things in their essays, reports or homework. These elements are usually very straight forward to mark for and you can be provided with ‘model answers’ or very clear sets of marking guidance (‘crib sheets’) – Your job is to
check whether or not these things are included, that facts are presented, that protocols are followed etc. This is time-consuming and requires attention to detail and concentration but because it is reasonable objective, does not require very much independent judgement.
However, at University, rarely is the whole of an assessment like this – usually there are also parts of the test or assessment task that will require your interpretation and that you will need to apply your personal judgement when using a set of more subjective guidance and assessment criteria.
You as a Marker
- Assessment and emotion
Being assessed and judged is always going to be an emotional experience. Think of how you feel, perhaps facing your own PhD viva or going for a job interview. Some methods of assessment will always strike us as being fairer and more just and appropriate than others and this is likely to be shaped by our past experiences of being assessed in these ways. How we have been assessed in School and before coming to University is likely to influence our views strongly. This may also involve cultural differences – in some countries (e.g. Italy) having oral, viva style assessments is much more common than in the UK. In some countries (e.g. China) assessments in School are highly selective and competitive – they are used to identify the one or two students who can go on and study at University.
· Hawk or Dove
Are you a tough marker (Hawk) or a more lenient marker (Dove)? All markers are required to use and interpret the marking criteria and apply them consistently to all the work they grade. However, particularly in divergent assessments, there is still room for these criteria to be interpreted slightly differently between markers and to be judged either more severely or more generously.
Do you begin marking with a view that the students start with 100% and as you mark they lose marks as they make errors, or do you start with the view that they begin with 0% and they win marks as they make accurate and correct responses in what you read?
Do you see it as your job to ‘punish’ mistakes or to ‘reward’ successes?
Very rarely are we purely ‘Hawk’ or ‘Dove’ but somewhere in between – being aware of your own nature as a marker is important – and something that you can test out with colleagues. Check your approach by sitting down with a group of peers to discuss the assessment criteria together before you begin to mark work individually. Do you all interpret them the same way and can you benchmark the standards you will use to ensure that you will be judging the achievement of the students at the same level. This can then be checked further by actually doing some ‘mock’ marking and comparing the grades you give and discussing any differences with your colleagues.
We do tend to have a ‘Marking Personality’ that we assume when doing any marking….once a Dove always a Dove (Haines, 2004)
So it is important to be self-aware as a marker.
2. Features of good quality assessment
The quality of assessments (as described by the Quality Assurance Agency, QAA) adheres to a number of features.
It should be valid, reliable and transparent. Ideally it should also add value and be viewed as a fair process for all the students.
- Valid assessment measures what it was designed to measure (i.e achievement of the learning outcomes of the module)
- Reliable assessments can be made by different markers to achieve the same result, or by the same marker at different times. It is greatly benefited by having very clear assessment criteria that guide the markers to judge and value the same things to the same standard.
- Transparency in assessment processes means ensuring the students know how and when their learning will be judged right from the very start of the module (actually even before this, when the students were choosing their modules). They should know what forms of assessment are going to used and how their performances in those tests will be judged (i.e. the standards that are being applied). Ideally students should be able to take formative assessments before they take a summative assessment (e.g. a mock test).
2. i. Fairness in assessment
A fair assessment is clearly a valid and reliable assessment that the students are properly informed about but what else does fairness imply?
Bias can take many forms…
Does the ‘test’ favour certain student attributes? Is it likely that some students will do better on the test because of who they are rather than what they have learnt and can do? e.g. Confidence in spoken English in real-time, oral examinations
Do you, as the marker, favour certain students or dislike others? Do you favour certain ways of thinking or particular ‘arguments’ in an essay? Do you have certain things that really irritate you if you read them in a student submission, (e.g. spelling or grammatical errors, the wild use of exclamation marks or the failure to label graph axes). There is a recognisable response called the ‘Halo effect’ – which can mean that a small but irritating mistake can make the marker view all other aspects of the work more negatively – and vice versa, a student who does something you really like (writes a wonderful introduction to their essay) can have the rest of their work viewed more positively.
This is clearly unfair and must be safe-guarded against.
To do this we use a range of strategies to avoid bias – anonymous marking (when the identity of the student is unknown to the marker), the application of clear and transparent criteria, (which can be double checked by both internal and external examiners) and our own monitoring and checking processes. We use Blind Double Marking and moderate our grading processes when we need to be assured that the assessment is as reliable as possible.
The course convenor, for the module that you are assessing, will explain the Assessment practices that you are required to follow but please also see the University rules on the Cardiff University Student Charter.
Providing a Level Playing Field
In the past, fairness was thought to be achieved by treating everybody the same – so all students sat the same test, in the same way, for the same length of time etc. Today we have a different view, today we aim to give all students the same opportunity to demonstrate that they have achieved the learning outcomes, to provide a level playing field. This may actually mean treating people differently according to their needs and abilities. Where this becomes a major concern is when we aim to assess students who have a disability, e.g. to give a dyslexic student a fair assessment they may be allocated additional time in a written examination; to assess a blind student they may be allocated a ‘scribe’ who can read out the questions and record the answers on their behalf etc.
This is clearly not an exact science and the needs of individual students need to be carefully assessed and taken into account in seeking to provide the level playing field for all learners.
3. Assessment Criteria and Marking Schemes
To judge how good something is a marker needs to be able to compare it with something, in other words to judge it against a standard. There are two common ways that we do this in Higher Education.
Norm-referenced assessment – compares the work of one student with that of his or her peers in the same cohort – effectively ranking the students and deciding how good the work is in relation to others in the class. The problem with this approach is that the absolute standard may well vary from one cohort to another and so the same piece of work could potentially get a different grade from one year to the next. This is particularly
true if the cohort size is small. This comparative approach can sometimes be referred to as, marking to the bell-shaped curve – as it assumes that the spread of marks for a typical cohort of students will be normally distributed (which may or may not actually be the case).
Criterion-referenced assessment - This second and recommended approach judges how well a student has performed against a pre-determined set of descriptive criteria. These criteria are tightly aligned to the learning outcomes for the module and seek to help a marker assess to what extent a learner has achieved them.
A minority of assessments in University are judged against simple Pass / Fail criteria,
i.e. that the students have either met or failed to meet the standard expected. Such an approach best suits professional exams in which a set of professional competencies are tested – typical say in Nursing clinical practice – a student is judged to be professionally competent or not.
However, the majority of modules are judged against a graded set of criteria in which students can demonstrate different levels of achievement. In this case the criteria seek to describe a range of standards and/or qualities that correlate with the grade boundaries. In essence they describe what an excellent, a very good, a good, a satisfactory and an unsatisfactory performance look like.
3. i. Why do we need Assessment Criteria?
There are a number of reasons why we need assessment criteria:
- To make goals of the assessment clear and transparent to the students.
- To make the standards explicit – which helps ensure assessments are valid and reliable as they can be.
- To aid discussion about assessment results between markers and between markers and students.
- To make marking efficient – once markers have loaded the assessment criteria into their heads, they know what they are looking for in the student work and can identify it quickly.
- For those who scrutinise the quality of our modules and courses, it is possible to check that the learning outcomes and the assessment criteria are in harmony.
3. ii. What are Assessment Criteria?
Assessment criteria explain to a learner what they need to do to get a particular grade. They clarify what is expected in terms of the quality of student performance. These standards are derived from a number of sources – they are shaped by the QAA Qualification Descriptors (that provide guidance on the standards expected at different degree levels, they are informed by the Disciplinary Subject Benchmarking statements that are given for each major discipline at Undergraduate Level and they are shaped by the Professional Bodies that accredit Programmes etc).
Assessment criteria are usually used to produce a marking sheet or pro-forma which invite the marker to make a judgement on the standard of the work and to provide a few words of justification for their decision. They may also provide space for the marker to give some feedback to the learner on how they performed in this task and feedforward guidance on how they can build on their learning and improve their grade in the next assessment task (See section 5. Providing Useful Feedback for further guidance).
Marking sheets may also need to indicate the relative importance or weighting of the individual assessment criteria – For example, the Accuracy of the Spelling and Grammar may be far less important than the Quality of the Argument and the Use of supportive Evidence, when marking an essay. This would need to be reflected in the proportion of the overall marks assigned to each criteria.
3. iii. Marking Schemes and how to use them
Alongside the assessment criteria markers may also be provided with additional marking guidance and a marking scheme. For example, a test question may have a model answer or a set of expected elements that would be included in a passing, good or excellent answer. A marking scheme can provide the mark breakdown for a multi- parted assessed task. For example, marking a laboratory report, there maybe 10 marks for the Introduction, 30 marks for the data and its analysis and 20 marks for the conclusion.
3. iv. Some examples of Assessment Criteria and Marking Schemes
UK Undergraduate degrees are graded using a standard marking scheme –
70 and above
60 – 69
Upper second (2i)
50 – 59
Lower second (2ii)
40 – 49 Satisfactory Third (3rd)
39 and below Unsatisfactory Fail
For further information – please see - http://www.internationalstaff.ac.uk/degree_classification.php?uni=37
However, in order to allocate the grades reliably more detailed information is provided in the form of assessment criteria and marking guidance – sometimes these are combined into Departmental marking sheets that are used across a range of modules and sometimes the guidance is very specific and has been designed to mark certain kinds of assessment tasks or even specific assessment questions.
4. Getting Started with Marking
4. i. Getting started
- Follow any marking guidance you have been provided with and keep looking back at it as you mark. Your module leader may provide a briefing on assessment or your department may issue guidelines.
- Print out the assessment criteria, model answer and/or marking scheme so that you have it in front of you as you grade.
- If you are not sure – ask for further advice from the module leader (he or she may also be willing to double mark a couple of your assessments to help you judge the level you should be grading to).
- Check what is expected in terms of the ‘feedback’ you should provide for the students. How much such you write, what form should it take etc? It can be very helpful if you can see an example of ‘good’ feedback from a past cohort.
- Ensure you keep yourself fresh – take regular breaks when marking
- Be self aware of any personal biases and preferences you may have and keep them in check
4. ii. Two general marking strategies
There are two general ways that people approach marking, especially when grading reports or essays. The Holistic Approach or the Analytical Approach. It is not so much about what is done but rather the order in which they are done.
Taking the Holistic approach the marker starts by reading the whole piece and giving an overall, based on a holistic impression, before then going on to do a more detailed analysis against the marking scheme. Seeking to clearly explain and justify the holistic grade in the process.
Alternatively adopting an Analytical approach you start with a more itemized implementation of the marking scheme. Perhaps awarding marks for each part of the answer according to a marking scheme or against each given criteria. Finally totting up the separate marks and seeing if the resultant overall mark feels right.
In practice it is important to do both – and then compare the holistic, more impressionistic result with a more detailed and analytical result. That way you build in a checking mechanism into the process and are more able to avoid ‘bias’ and the ‘halo effect’.
4. iii Checking your marking
When you have marked all the assessment tasks you could then…
- Re-mark a sample (5-10%) a day or two later to check your grading.
- Swapping scripts with peers and/or the course convenor can help you benchmark your standards and approach. If the marking that you are doing is
Summative the Cardiff University Regulations require that 25% (including all ‘Fails’ and ‘Borderline’ scripts will be double marked).
- Come back to the marked papers a day or two later and re-mark a couple.
- Check how long it is taking you to grade and compare this with peers – when you have a little more experience, set yourself a time budget for grading and stick to it.
5. Providing Useful Feedback
Giving helpful and constructive feedback is probably one of the most useful things you can do for a learner. Getting a realistic sense of how you are doing, what you can now do well, what you need to focus on next etc is so valuable. Think of your feedback as ‘teaching at a distance’ rather than justifying the mark you have given and you will more readily strike the right tone.
“Feedback is one of the most powerful influences on learning and achievement.”
Hattie J. and Timperley H. (2007) The Power of Feedback. Review of Educational Research 7 77: p. 81
The University has developed a comprehensive Feedback Policy available at http://assessmentmatters.hosting.cf.ac.uk/assessmentmatters/wp-content/uploads/2011/06/Academic- Feedback-to-Students-Policy-and-Guidance.pdf
It highlights three important Principles:
Principle 1: Feedback supports and promotes effective learning. Principle 2: Feedback is a continuous process
Principle 3: Feedback needs to be suited to individual students’ needs
(See section 5.ii for further discussion of what these principles look like in practice)
5. i. Why do we give Feedback?
If you were to spend 10 minutes looking back at feedback you have received, perhaps from your supervisor, you will see that Feedback aims to do lots of different things including –
- To encourage and motivate
- To point out and correct mistakes
- To re-explain key concepts
- To recognise and reward good work and ‘behaviours’ that are desirable
- To notice and penalise poor work and discouraged behaviours
- To suggest further reading
- To extend and deepen thinking – to point out ‘next steps’ Can you add anymore?
As you write feedback it can be useful to identify what kind of feedback you are trying to give – this can be best achieved by focusing on what you would like the student to do, ideally, having read your feedback.
5. ii. What does ‘Good Feedback’ look like?
A working definition of written feedback could be –
Comments we provide on a student’s work that are written with the intention of helping the student do it better next time.
Bearing in mind that our students are unlikely to be asked to do exactly the same thing again – I definition may be better stated as
Comments we provide on a student’s work that are written with the intention of helping the student learn from this assessed task so they can improve their performance in the next task.
Using this – what do you consider are the features of really helpful feedback – please add to the list below.
Good feedback is –
- Honest (The comments mean nothing if they are not a truthful representation of your assessment – try and make it clear whether the comment is a factual or opinion, is your comment about the factual accuracy of their work or a judgement about its quality.)
- Timely (provided whilst the students can still remember what they did in the assessed task so that the feedback has relevance for them.)
- Specific (explaining what exactly was ‘good’ or exactly how they should improve).
- Personal – acknowledging the work is from an individual and trying to tailor the comments you make to them. Using their name in the feedback may help.
- Balanced – the student needs to know when they have done something wrong or badly but they also need to know when they have done well.
- In harmony with the grade – the tone of the comments should reflect the overall grade.
- Prioritised – If a student has made lots of mistakes it is probably more useful to prioritise in relation to their importance and focus on the most important in this set of feedback – i.e don’t feel you need to be thorough and mention everything – but focus on two or three things that the student could realistically tackle next time. (The grade given will clearly take all your concerns into account).
- Respectful – recognises and rewards the time and effort that students have invested in the work.
- Kind and encouraging – Even ‘bad news’ can be delivered in a constructive and kind way. Try and phrase your comments in a ways that a student is more likely to read it and think…’yes I can do that’ rather than reading it and feeling crushed and undermined.
- Linked to the Criteria – feedback can often be crafted with explicit reference to the assessment criteria – showing the mark scheme and where a student has lost or won marks.
These values are clearly represented in The University’s Policy on Academic Feedback to Students which is based upon three following principles:
* Feedback supports and promotes effective learning;
- Feedback is a continuous process;
- Feedback needs to be suited to individual students’ needs.
The underlying view here is that feedback is key in supporting student learning and provides a huge opportunity to engage students in an on-going dialogue with teachers and peers about their learning. You are therefore encourage to see ‘giving feedback’ as one of the most important things that you can do for your students and not as a ‘job’ to do as quickly as possible.
5. iii. Written Feedback - Some dos and don’ts
- Always include positive, praising, reinforcing comments alongside more critical, correcting and error-noting comments. You may like to use the ‘Feedback sandwich’ approach which recommends giving the positive comments first, then giving the criticism and finishing on a note of praise.
- Always try and be constructive in your feedback - some people coin the phrase “Feed-forward” to indicate this. The comments you write should try and indicate to the learner what they can do to improve their work and not simply point out it what was wrong or poor.
One way of doing this is to try and communicate three things to the student –
- Your honest judgement of what they have done/achieved this time
- The goal they should be aiming for next time
- Practical suggestions on how they can achieve this next time.
- If you can – type up the comments you make, if you can’t do this, take the time to write clearly and legibly.
- Try to make the feedback you give to your students really meaningful – use example from the student’s own work to illustrate the points you want to make and try and model the standards you expect.
- Your feedback should be respectful and written in inclusive and non- discriminatory language. When you have written your comments look back at them and imagine if you would be comfortable saying them to the student in person.
- If students have the opportunity to talk about their feedback it is more likely that they will understand and act upon. It maybe that you can chat through your feedback comments with the students in the next class or in your office hour or you may be able to prompt such a conversation to take place between students so they can talk about their feedback with each other.
- Can you encourage the students to self-assess and evaluate their own work. You may be able to ask them how they felt it went or how they judged the quality of their own work before you give your views. Ultimately we want students to be able to judge the quality of their own work – after all when they graduate and leave Cardiff University they will not have you looking over their shoulder and checking what they are doing. Learning how to self evaluate is going to be a valuable skill for them to develop.
5. iv. Further thoughts on Feedback
Feedback is clearly something our students place great value on – and have been critical of in the past. It can be challenging to maintain the highest standards in providing rich and timely feedback for learners particularly as class sizes have increased and staff time has become evermore pressured. Therefore, it is important that the feedback provided is useful and good quality but also that the students are encouraged to make full use of the feedback they receive.
There are currently a number of developments in feedback happening at The University. Colleagues are experimenting in providing automated feedback through the design of QuestionMark Perception on-line quiz/tests in which the students get immediate feedback on their answers. In Health disciplines the use of GradeMark (Part of the Turnitin software package) is being implemented to improve feedback on assignments submitted via Learning Central and in Chemistry, Psychology and Pharmacy staff are actively exploring the use of providing audio feedback to students.
To find out more please take a look at the Learning and Teaching Support pages on Feedback at http://learning.cf.ac.uk/tags/feedback/
In addition to exploring better ways of providing feedback The University is keen to encourage students to make full use of the feedback they receive. At University feedback can take many forms, e.g. individual, group, verbal, written, formal and informal. Students may not recognise this variety and may struggle to apply the feedback they are given. These issues are also being discussed at The University.
6. Two Assessment Challenges
6. i. ‘Exam Panic’ and assessment nerves
All assessments are important to the students and some may get anxious particulary when taking timed examinations and Vivas. Your students may show signs of this in the classes you teach and be particularly so in the first year (when they sit their first University examinations) and in the final year (when the assessments are clearly high stakes). You may be able to suggest ways in which they can tackle their revision or self test their own understanding and knowledge using past papers etc but this is likely to be
covered by the module leader. It can be very helpful to talk about this with the module leader – are there any particular approaches that s/he recommends that you can reinforce when you are teaching the students? For example, can you decode the Assessment Criteria with them during a tutorial or in the practical class? Can you work through similar styled and focussed discussion questions so that students are familiar with the way their learning will be judged in the summative assessments, etc.
Although you can be clearly sympathetic and understanding when students express such concerns to you – do not try to be their counsellor and avoid giving a false sense of security… “I’m sure you will pass, it will be fine”.
If the students have any procedural questions about their exams you can direct them to the University Registry Examination Information pages at http://www.cardiff.ac.uk/regis/sfs/exams/ particularly the Information for Current Students pages.
If you are concerned that the student is overly worried and panicking about the exams, consult with the Module Leader, encourage them to speak with their Personal Tutor and if necessary point them towards The University Counselling Service at http://www.cardiff.ac.uk/counselling/students/index.html
6. ii. Cheating and Plagiarism
It is likely that as a Postgraduate Student you will be involved in marking a variety of forms of course work – these may be essays or laboratory reports, field work write-ups or sets of mathematical/statistical homework problems.
If students are cheating in this kind of work they are usually plagiarising, i.e. trying to pass somebody else’s work off as if it were their own, in order to get higher marks.
The cheating can be unintentional - the student may not realise that by not properly citing the source of the book or paper that they have taken an idea from that this is plagiarism; or they may have copied and pasted a paragraph from the internet and not enclosed it in quotation marks and referenced the source. A common mistake is when a student uses too many words from the original source when they are trying to paraphrase. Such ‘cheating’ is often down to poor academic writing skills and you should see your primary role as that of ‘teacher’. Can you show them what they have done is wrong and guide them on how to do it correctly next time? There are some excellent resources at Cardiff to help you with this (Please see Further Resources at the end of this chapter) including some really helpful on-line guidance. I particularly like the on-line tutorial in Avoiding Plagiarism provided by Information Services at https://ilrb.cf.ac.uk/plagiarism/tutorial/index.html. It can be very helpful to raise this with the module leader and to share the responsibility for this at an early stage. Usually, first-time ‘offenses’, particularly in the first year, are treated as learning opportunities and students are supported to avoid such difficulties in the future.
The literature also highlights that we sometimes detect higher levels of this kind of plagiarism in groups of non-native English speaking students. Possibly because they are less confident when it comes to paraphrasing and putting things into there own words. It is also likely that a non-native English speaker will be less able to detect the subtle differences in writing style that a native speaker is more aware of – and so a ‘cut and paste’ approach to writing a report or essay will be easier to spot as a reader.
A number of Schools ask their students to submit their work through a plagiarism detection tool called Turnitin. This software effectively looks for how much of the student’s work matches other on-line sources. Whilst some degree of similarity is expected a high match rate will trigger an alert so that a human marker can check whether the student has plagiarised.
A small proportion of students set out to cheat – they maybe very pushed for time or panicking that they can’t do the work on their own. They may ‘borrow’ a friend’s assignment or laboratory report and ‘copy it’ or they may even commission somebody else to do the work for them. Sadly this has become an internet business opportunity these days. However, this form of intended plagiarism is still uncommon but clearly a much more serious case of plagiarism.
Detecting a possible case of plagiarism is one thing but proving it is quite another. The University Registry have put together a web page giving links to University Policy, Staff Guidance and Fair Practice at http://www.cardiff.ac.uk/regis/ifs/plag/index.htmlBut this is such a challenging area that the main advice is – don’t act alone and take matters into your own hands. Take your concerns straight to the module convenor or your supervisor and involve academic staff earlier rather than later. In short - you should not be accusing a student of plagiarism but taking your concerns to the module leader.
Further reading suggestions
Haines, C. (2004) Assessing Students’ Written Work: marking essays and reports. A Key Guide for Effective Teaching in HE Routledge Press
Hattie J. and Timperley H. (2007) The Power of Feedback. Review of Educational Research 77 (1) p81-112
Knight, P. (ed 1995) Assessment for Learning in Higher Education London: Kogan Page 1995 ed. ISBN 0-7494-1533-0
Quality Assurance Agency Code of Practice – Quality and Standards in HE: Assessment of Students, (2000).
Rust, C., Price, M. & O’Donovan, B. (2003) Improving students’ learning by developing their understanding of assessment criteria and processes, Assessment and Evaluation in Higher Education, 28(2), 147–164.
Torrance, H. & Pryor, J. (2001) Developing formative assessment in the classroom: using action research to explore and modify theory, British Educational Research Journal, 26(5), 615- 631.
Quality Assurance Agency (2006) Code of practice for the assurance of academic quality and standards in higher education - Section 6: Assessment of students - September 2006 [WWW] http://www.qaa.ac.uk/Publications/InformationAndGuidance/Pages/Code-of-practice- Section-6.aspx
National Union of Students, Feedback: What you can expect [WWW] http://www.nus.org.uk/en/advice/course-reps/feedback/feedback-what-you-can-expect-/[Accessed 02/01/12]