The National Survey transitioned from a face-to-face to telephone based survey, which may have influenced respondents answering of the material deprivation questions
Mae’r Arolwg Cenedlaethol wedi newid o arolwg wyneb yn wyneb i arolwg dros y ffôn, a allai ddylanwadu ar ymatebwyr sy’n ateb y cwestiynau amddifadedd materol.