Every member of the group gets a collective mark for the product but each individual gets a separate mark for their group contribution.
In the Statement of Assessment Methods, the product is worth a certain percentage while the group contribution is worth a distinct percentage.

For example: group assignment = 10%; group contribution = 10%; other assignments = 80%.

There are a number of ways to obtain an individual mark for group contribution e.g. observer mark, or...

Self -reflection exercise
Provide a one-page commentary on the effectiveness of the team and the effectiveness of your own contribution to the team. The key questions you should consider include:

How well did the team function?
How well did you as an individual contribute to the team?
What might you personally have done to contribute more or better?
What outcomes did the team achieve and what are your thoughts and feelings regarding these?
If the team were to work together on another assignment what strengths could be built upon?
What opportunities for improvement are there?

or ...

Self- and peer-assessment

"Teachers have limited access to the knowledge of their students and in many ways students have greater insights into their own achievements." (Boud and Falchikov, 1989)

The main advantage of self- and peer-assessment is that the assessment is being undertaken by the main observers i.e. the group members. For a comprehensive guide to self- and peer-assessment with case studies, see ‘Self- and Peer-Assessment: Guidance on Practice in the Biosciences'.

There have been many studies on self- and peer-assessment which show that self- and peer-assessment agrees with teacher assessment when the process is well designed and implemented. For details see:

FALCHIKOV, N. & BOUD, D. (1989) Student Self-Assessment in Higher Education: A Meta-Analysis. Review of Educational Research, 59, 395-430.

FALCHIKOV, N. & GOLDFINCH, J. (2000) Student Peer Assessment in Higher Education: A Meta-Analysis Comparing Peer and Teacher Marks. Review of Educational Research, 70, 287-322.