The information extraction, quality assessment and weight of evidence work was carried out based on reading the full text of items that had met the screening criteria at Stage 2.
Cynhaliwyd y gwaith echdynnu gwybodaeth, asesu ansawdd a phwysau’r dystiolaeth ar sail darllen testunau llawn yr eitemau a oedd wedi cwrdd â’r meini prawf sgrinio yng Ngham 2.