One of the main reasons why the WNWRS was developed was to remedy a number of data quality concerns with the previous data collection method.
Un o'r prif resymau dros ddatblygu WNWRS oedd bod angen mynd i'r afael â nifer o bryderon o ran ansawdd y data a gasglwyd gan ddefnyddio'r dull casglu data blaenorol.