O dan y system, mae pedwar categori - gwyrdd, melyn, oren a choch. Ystyrir mai'r gefnogaeth leiaf sydd ei hangen ar ysgolion yn y categori gwyrdd, tra bod ysgolion yn y categori coch wedi'u nodi'n rhai y mae angen y gefnogaeth fwyaf arnynt.
Under the system there are four categories - green, yellow, amber and red. Schools in the green category are deemed to be in need of the least support while schools in the red category are those identified as needing the most support.