Some of the older cohorts present in the KS3 data would have moved into KS4 and so their results would be included in both indicators.
Byddai rhai o'r carfannau hŷn sy'n bresennol yn y data CA3 wedi symud i CA4 ac felly byddai eu canlyniadau'n cael eu cyfrif yn y ddau ddangosydd.