O'r 167 maes, mae 64 y mae Llywodraeth y DU yn eu hystyried yn gymwys i Gynulliad Cenedlaethol Cymru. Mae'r dadansoddiad ei hun yn gwahanu'r meysydd sy'n gorgyffwrdd i nifer o grwpiau:
Of the 167 areas there are 64 which the UK Government considers to apply to the National Assembly for Wales. The analysis itself separates the different intersecting areas into several groups:21 - where no joint action will be required upon exit from the EU;19 - where non-legislative frameworks may be required;24 - where there is the potential need for a legislative framework; and12 - areas that the UK Government believes are wholly reserved.