>> i am adele morris the policy director for climate and energy project here at brookings. my question is about the scoring of a bill that's got a lot of complicated elements in it that are not simply just fiscal policy or tax policy. so for example, let's suppose we had a bill that imposed an excise tax on carbon content and fossil fuels for example, and some of that revenue buys down business tax rates, for example, so you've got the kind of question of how you're going to dynamically score a tax swap maybe with additional elements in there. but then what if also, there's a regulatory reform in there that says we're going to suspend clean air act regulations on stationary sources? how do you or do you deal with that and also, in that context would there be a change in how cbo would score an excise tax because they have the standard 25% haircut on the gross revenues of excise taxes? would the dynamic score change that? >> all right. let's get an answer to that. >> i would hate to be confronted with that issue but excise taxes do have allocation effects and labor. an excise