The Barnett formula under the Smith Reforms

With the implementation of the Smith Commission reforms, there will be abatements to the Scottish government’s block grant as calculated by the Barnett formula, to allow for the tax revenues which Westminster will forego. The income tax abatement will be increased through time in an arrangement known as Holtham indexation. The purpose of this paper is to model these new fiscal arrangements. The modelling implies that, other than in an unlikely special case, the system cannot run on indefinitely with fixed parameter values, without reaching relative values of per capita public expenditure in Scotland and England which would be politically unacceptable. Moreover, there is a likelihood of adverse dynamic effects which would further destabilise the system. The paper also puts forward an adjustment to the original form of Holtham indexation, to take account of relative population growth. While not answering every problem, this adjustment has strong equity arguments in its favour, and would also significantly stabilise the system. It is particularly important that the implications of this type of modelling should be taken on board by policy makers and parliamentarians just now, when the detailed legislative and other arrangements for implementing the Smith reforms are about to be finalised.