The PCR (regulation 60), and UCR (regulation 80) set out exhaustive lists of means of proof which could be used by contracting authorities to assess standards of technical or professional ability.
Mae gwybodaeth ansawdd a methodoleg am gryfderau, cyfyngiadau a defnyddiau priodol, ar gael yn y ddogfen Gwybodaeth Ansawdd a Methodoleg am yr Arolwg o’r Llafurlu (y Swyddfa Ystadegau Gwladol).