Professor Alan Barrett:

The up-to-date part is simple; the pooling across waves less so. The survey is collected every year. If one starts adding waves together, so that one is not just dealing with one year's data in the model but two or three years' data, that means that one has much bigger sample sizes and can start looking at, for example, the effect of welfare payments that are received by a relatively small group of people. I can give one example that came up recently, which I hope is a good example. An examination of the effect of housing-related payments was difficult with the original switch because such payments are not like unemployment or pension payments. The number of people involved is smaller and therefore the data was not so robust but the additional data work that has happened there is going to allow for richer analysis.

Deputy Burton asked a broader question which is an interesting one, on the advantages and disadvantages of switch. I have already touched on the advantages in terms of the fact that there is simply no other way to get that population-level sense of the distributional impacts if one is not doing switch-type analysis. That advantage is clear. The downside, of course, is what is not included although we have tried to extend things. One of the big innovations we are working on at the moment is the issue of medical cards, for which I should give my colleague Dr. Tim Callan and his team credit. The issue of medical cards has now come on the agenda. The Department of Health will become a co-funder of the switch model with a view to factoring in medical card entitlement and impact. That is a very significant addition -----