  By using the general triaxial rotor model (TRM) and the phonon-configuration
mixing scheme within an anharmonic-vibrator(AHV) framework, a series of global
correlations between electromagnetic properties of nuclear $2^+_1$ and $2^+_2$
states are analytically established. The correlations from both models can
roughly describe the experimental data involving quadrupole collectivity with
few exceptions. Furthermore, there seems to be a robust orthogonal
transformation between the AHV and TRM bases for realistic nuclear systems,
suggesting that the two models may in fact be describing the collective
features of nuclear low-lying states in similar model spaces.
