I believe that takes a number of different strands. In terms of the tax expenditures report, every year we re-cost every single expenditure. That allows us to see if there are divergences from what we would expect, and then we look at those. So that's a monitoring approach.
We also continually look at proposals that come from various quarters to change tax expenditures. So when we look at an adjustment to a tax expenditure, we effectively treat it as a new proposal. We take that opportunity to apply the analytical framework the Auditor General referred to to the whole measure, with the benefit of some data in that case.
We also select particular tax expenditures for an in-depth evaluation. This year we published an evaluation of the charitable donations tax credit. We selected that measure because there's a widespread interest in it throughout the voluntary sector; it's an expensive tax measure if you calculate it in tax expenditure terms; and it's one that we believe is particularly important. So we did an evaluation of that and published it.
I'd say there's a wide range of approaches. I think the Auditor General's observation that there's a requirement to be systematic, we take to heart. We are going to look at ensuring that across all of those approaches, we're covering all of the bases, and that to the extent there are gaps, we will make sure they are filled.