However, in the second round of fieldwork these were supplemented with online interviews for participants who did not have a telephone number or preferred to do a shorter online survey.
Fodd bynnag, yn ail rownd y gwaith maes ategwyd y rhain gan gyfweliadau ar-lein ar gyfer cyfranogwyr nad oedd ganddynt rif ffôn neu a oedd yn well ganddynt wneud arolwg ar-lein byrrach.