How can we calculate value of a new change?

How can we calculate value of a new change? What tools are there to evaluate product value?

PLEASE NOTE: we need your full name and you will need to bring photo ID to show security at The Shard.

Please note that RSVPs close on Sunday 14th April.

We encourage members to take photographs and videos during our sessions. If you are not happy for images of you to be posted on the internet/used to publicise the group, please do not attend this event.