Professor Eoin Reeves:

It is actually social costs and social benefits. The CBA that was used in this case was complete and looked at all those costs and benefits. The tricky part is the benefits. KPMG, as I understood it, looked after the costs - we talked about that - but PwC was commissioned to look specifically at the benefits. We are talking about social benefits here. Identifying them is one big challenge, and one has to make choices. The tricky part is monetising or putting the value to them.