Jess Turner (UNISON) said that in providing feedback people tended to focus primarily on the services they use producing a biased picture.
Dywedodd Jess Turner (UNSAIN) bod pobl, wrth ddarparu adborth, yn tueddu i ganolbwyntio'n bennaf ar y gwasanaethau maen nhw'n eu defnyddio gan gynhyrchu darlun rhagfarnllyd.