A key question surrounding the FairTax is whether the tax has the ability to be revenue-neutral; that is, whether the tax would result in an increase or reduction in overall federal tax revenues. Economists, advisory groups, and political advocacy groups disagree about the tax rate required for the FairTax to be truly revenue-neutral. Various analysts use different assumptions, time-frames, and methods resulting in dramatically different tax rates making direct comparison among the studies difficult. The choice between static or dynamic scoring further complicates any estimate of revenue-neutral rates.