Pearse Doherty (Donegal, Sinn Fein) | Oireachtas source

That is quite interesting and it clarifies my own views on this matters well. The Department will have a very strong view that there will be no second set of costings. The Department of Finance costing are the costings. The Department of Public Expenditure costings are the costings and the question is then what does one do, as Professor McHale mentioned - is it just a clearing house, where one filters these costs through or is there a validation?

One of the issues I have been trying to get to the bottom of is the cost of abolishing the USC. This has been debated for the past two years. We have costs provided to us by the Department of Finance on a number of occasions that it would cost €3.7 billion because that is the amount it would cost to abolish the USC this year.

However, the Department of Finance tells us a phased abolition of the USC cannot by costed, even when we give it the figures by how much we want to reduce it year by year. The Department can tell us how much it will bring in each year, up to €5.4 billion by 2021, but it cannot tell us the cost of abolishing the USC on a phased basis.

Using that as an example, does Professor McHale believe that when the Department of Finance says it knows the USC will bring in X amount each year up to 2021 and knows if it abolishes it in 2017, it would cost X amount but phasing it out in the way described, the independent costing units would have the ability to come in and say that can be costed or assumptions can be made that can provide costings, because every costing is based on a certain assumptions?