The activity will comprise a nominal amount of marks. This is so the exercise is of value to them and they will take it seriously but it will not have a huge impact on their final mark. Let’s say about 5%.
People are allowed to update their choice as often as they like but they must make a choice between the two.
You set a deadline. This can be as short or as long as you like. Use the Restrict answering to this time period options in the Moodle choice activity to define when the deadline is.
Set a number (say 5) based on the size of the class. If the smaller group can get to be this size or less then they get 10 marks each.
People are allowed to do deals where they give marks to others.
People are free to negotiate however they feel. I would allow negotiations to happen on a forum that you create as well as by other means. You could try and restrict negotiations to only on the Moodle forum but I think this will be hard to police so we may as well just allow other communication. The forum will be useful in a strategic way as it is open to everyone to see and is also proof that a conversation actually happened. Create a separate forum for where people can agree to mark swapping. For Mark swaps to be legal they must be stated on this forum and they must have a reply by the other part acknowledging it.
If I end up in the winning team I agree to give 2 marks to this person.
All agreements on the Swaps forum after the closing date are final and will be awarded. You can’t say if I win with 4/5 I will give a number of marks and if I win with 10/5 I will give more. It is just a single number.
You can spice up the forum by starting a few conversations based on some of the ideas here.
What you can do is run this over several days. Take a note of the numbers in the group and how they change over time. This can be the basis for discussion at the end as well as the final result. You and the whole class can learn a lot not just about negotiation but also human behavior from this exercise.
The rules above and the numbers are just suggestions. Feel free to change and tweak them based on your class and it’s characteristics. This can be a very fun exercise that people learn a lot from.