O ran y broses adolygu ei hun, mae meini prawf sefydledig y mae’n ofynnol i’r Comisiwn eu hystyried wrth gynnal adolygiadau. Mae’r rhain yn cynnwys, cyn belled ag sy’n bosibl, sicrhau cysondeb yn nhermau nifer yr etholwyr i aelodau etholedig ym mhob ward etholiadol yn y sir neu’r fwrdeistref siriol, sefydlu a chynnal ffiniau sydd yn hawdd eu hadnabod ac osgoi torri’r cwlwm lleol wrth argymell ffiniau ar gyfer wardiau etholiadol.
In terms of the review process itself, there are established criteria which the Commission is required to consider when undertaking reviews. These include, as far as possible, ensuring consistency in terms of the number of electors to elected members within each electoral ward of the county or County Borough area, establishing and maintaining easily identifiable boundaries and the avoidance of breaking local ties when recommending boundaries for electoral wards.