We describe, within an ab initio approach, the stabilization of the tetragonal phase versus the monoclinic one in yttrium-doped zirconia. The process is believed to be influenced from different mechanisms. Indeed, we show that there is a delicate balance between the change in electrostatic and kinetic energy and exchange-correlation effects. In the tetragonal phase, the perturbation induced by doping is better screened at the price of sacrificing correlation energy. Our work opens the opportunity to use the same approach to predict the tetragonal phase stabilization of materials such as zirconia or hafnia, with different and less characterized dopants.