In reaching the decisions outlined in this review, ministers drew on existing evidence and considered the cumulative impact to enable a high-level analysis of the changes to be conducted.
Wrth ddod i'r penderfyniadau a amlinellir yn yr adolygiad hwn, defnyddiodd y Gweinidogion dystiolaeth bresennol yr IIA ac ystyried yr effaith gronnol i hwyluso dadansoddiad lefel uchel o'r newidiadau.