Numerous organizations have been set up to reform tax systems worldwide, often with the intent to reform income taxes or value added taxes into something considered more economically liberal. Other reforms propose tax systems that attempt to deal with externalities. Such reforms are sometimes proposed to be revenue-neutral, for example in revenue neutrality of the FairTax, meaning they ought not result in more tax or less being collected. Georgism claims that various forms of land tax can both deal with externalities and improve productivity.