Laffer curve rates (for example, in the United States by the Congressional Budget Office). While the interaction between tax rates and tax revenue is generally accepted, the precise nature of this interaction is debated. In practice, the shape of a hypothetical Laffer curve for a given economy can only be estimated. The relationship between tax rate and tax revenue is likely to vary from one economy to another and depends on the elasticity of supply for labor, as well as various other factors. Even in the same economy, the characteristics of the curve could vary over time. Complexities such as progressive taxes
Notional election results local government wards, and it is the results from local government elections that are the primary source used to calculate notional results at a constituency level. Professors Colin Rallings and Michael Thrasher of Plymouth University have been involved in calculating notional results for general elections since 1992 where periodic boundary changes have taken place. The data compiled from their work has been used by several prominent media companies including television channels for the purposes of comparing one general election result to the last. Notional results have their limitations in that voting patterns may well have been different had new boundaries