Schools with high attendance levels tend to have high levels of attainment at all key stages, but those with low attendance levels tend to have low attainment levels.
Mae ysgolion â lefelau presenoldeb uchel yn dueddol o gael lefelau uchel o gyrhaeddiad ym mhob cyfnod allweddol, ond mae'r rhai â lefelau presenoldeb isel yn dueddol o gael lefelau isel o gyrhaeddiad.