We have a rather complex system that depends on the year of study. For anything but the final year, there is a system of moderation rather than second marking, where a second member of staff reviews the marks given bt the first marker, knowing what they are. In the final year, marking is supposed to be double-blind: we do not know which student's work we are marking and the second marker operates completely independently of the first (easy for electronically submitted assignments, less so for unseen exams). The marks are then compared. If within say 3 % points we take a mean, or the highest. If it is greater, we have a meeting. We are to document such a meeting. If we agree a mark, this mark and the meeting minutes are available to the external examiner. If we cannot agree, this is also reported to the external, though sometimes a third marker may be invited. It is rare for the external to overturn an agreed mark.

In practice, specially with small classes, we usually know which student is which (the anonymity was introduced in particular to overcome any gender bias. I and my colleagues do not seem to have been guilty of this).

Usually, but not always, independent marks are very similar, and the rank order is much the same. Occasionally, one of us has been more generous than the other.

It is a fair but cumbersome process

We would use a second marker only if there was doubt about a border-line pass/fail or maybe a difficult distinction/no distinction decision.

The second marker would be the external examiner. We would ask the external examiner to make a recommendation about the particular case, in addition to the external examiner's usual duties.

The usual duties are to certify: the suitability of the original question paper and examiner's memo, the marking standard, the standard of the course and even syllabus. – The external examiner was expected to make general, helpful remarks to improve the course. (An external examiner would typically be requested from industry or from another university in the country.)

The usual duty of the external examiner is not to remark all scripts. This is because only the lecturer knows how detailled the lecture was.

My experiences in roles of external examiner and examiner were always helpful, useful and positive.

We have a rather complex system that depends on the year of study. For anything but the final year, there is a system of moderation rather than second marking, where a second member of staff reviews the marks given bt the first marker, knowing what they are. In the final year, marking is supposed to be double-blind: we do not know which student's work we are marking and the second marker operates completely independently of the first (easy for electronically submitted assignments, less so for unseen exams). The marks are then compared. If within say 3 % points we take a mean, or the highest. If it is greater, we have a meeting. We are to document such a meeting. If we agree a mark, this mark and the meeting minutes are available to the external examiner. If we cannot agree, this is also reported to the external, though sometimes a third marker may be invited. It is rare for the external to overturn an agreed mark.

In practice, specially with small classes, we usually know which student is which (the anonymity was introduced in particular to overcome any gender bias. I and my colleagues do not seem to have been guilty of this).

Usually, but not always, independent marks are very similar, and the rank order is much the same. Occasionally, one of us has been more generous than the other.

It is a fair but cumbersome process

I have rather strong views on this topic. If work is single marked, then it relies only on the judgement, commitment and ability of one person. IMO, the position, titles or qualification the person holds is no guarantee of fairness or diligence. Single marking does not promote transparency, and does not represent a robust quality assurance system for award giving HE institutions.

Rather than see this as a criticism or threat to professional integrity etc, markers should embrace double marking, internal moderation, exam boards and external sampling (all of which featured strongly in my previous working practice), and see them as something that ensures a quality of service delivery, verifies a markers judgement, and promotes transparency. I never has any qualms about students, auditors or external examiners querying any grade I awarded, as there were set marking criteria, and the system guaranteed that a students work had been checked at multiple levels. Yes, there were odd times when markers disagreed (beyond a grade level), but the final award represented a fair consensus of the students performance against published and agreed standards.

From my own perspective, and reflecting the views I have expressed, I have an innate distrust of systems that  are not transparent, do not have published and detailed marking criteria, and do not have at least two levels of documented marking, prior to going to a formal exam board for verification.

Moreover, if there is room for speculation about the systems of the awarding institution, then there is room for doubt about the awards it issues.  IMO, double marking is an integral part of HE quality assurance, and a service we provide to both students and society. Yes, this is an onerous undertaking .... but it's what we signed up to do when we entered the HE teaching profession. 

There is revaluation system. Students have apply with requisite fee for revaluation.

Subhash:  So am I right in understanding that a students work is marked by a single person, then, if the student is unhappy with the mark, they can have it re-evaluated (presumably by a different marker), but they have to pay a fee for the service?

We have a single marking at our university,  however each subject has 2 staff as they marking complementary for each part as they  teach. single marking is great trust but in some places must remarked for fairness issues.