Multiple area registrations – where someone may be registered with more than one different GP practice and also hold more than one NHS number (likely impact: over-coverage)
Cofrestriadau mewn sawl ardal – lle gall rhywun fod wedi'i gofrestru gyda mwy nag un practis meddyg teulu gwahanol a hefyd yn dal mwy nag un rhif GIG (effaith debygol: cwmpas gormodol);