 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 . 
