Mists of Pandaria Classic Shadow Priest Stat Priority

The stat priority for Shadow Priest is as follows:

1. Intellect;
2. Hit Rating / Expertise / Spirit (15%);
3. Haste Rating;
4. Critical Strike Rating;
5. Mastery.

Intellect is the main stat for all casters as it increases their Spell Power, boosting the effectiveness of damage and healing spells. Intellect will be found on all gear you use and will continually increase throughout the expansion as your gear steadily improves.

As it has been the case for all previous iterations of the game, maxing out your Hit Rating (or Spirit in this case, which is converted to Hit Rating via Spiritual Precision). You can use either of these stats to reach the 15% spell hit cap, ideally using Spirit to also increase your mana regeneration at the same time. Mists of Pandaria changes Expertise, making it increase spell hit chance; you should not go out of your way to use Expertise, as Spirit is simply better, but you may have some available from a racial spell.

Shadow benefits greatly from reaching certain Haste Rating thresholds, as this will give your spells additional ticks of damage, greatly increasing their damage output. Below are the effective Haste percentages requirements to gain additional ticks of damage on your damage-over-time spells. These tables are calculated with raid buffs in mind.

These are the haste requirements for non-goblin races:

Ticks Gained (Non-Goblin)	Devouring Plague	Shadow Word: Pain	Vampiric Touch
1 Extra Tick	3.12% Haste	3.16% Haste	4.75% Haste
2 Extra Ticks	18.97% Haste	19.02% Haste	23.81% Haste
3 Extra Ticks	34.99% Haste	34.93% Haste	42.82% Haste
4 Extra Ticks	50.81% Haste	50.81% Haste	61.92% Haste
5 Extra Ticks	66.64% Haste	66.64% Haste	81.00% Haste
6 Extra Ticks	82.62% Haste	82.50% Haste	100.10% Haste
7 Extra Ticks	98.61% Haste	98.48% Haste	119.02% Haste

These are the haste requirements for Goblins, thanks to Time is Money:

Ticks Gained (Goblin)	Devouring Plague	Shadow Word: Pain	Vampiric Touch
1 Extra Tick	2.10% Haste	3.16% Haste	3.71% Haste
2 Extra Ticks	17.79% Haste	19.02% Haste	22.59% Haste
3 Extra Ticks	33.65% Haste	34.93% Haste	41.40% Haste
4 Extra Ticks	49.31% Haste	50.81% Haste	60.32% Haste
5 Extra Ticks	64.99% Haste	66.64% Haste	79.21% Haste
6 Extra Ticks	80.81% Haste	82.50% Haste	98.02% Haste
7 Extra Ticks	96.65% Haste	98.48% Haste	116.85% Haste

Critcal Strike provides a moderately high value, as all of our spells can crit. Mists of Pandaria improves Crits across the board, making all spells and abilities crit for 2x damage; previously, casters would only crit for 1.5x damage, greatly improving this stat for DPS. Crits also trigger a Shadowy Apparitions, further improving your damage./

Shadow gets Mastery: Shadowy Recall for their Mastery trait, givng your periodic Shadow spells a chance to deal damage twice. While this is at the bottom of the list, it is still a decent stat to grab as DoTs are the main part of this spec; don't shy away from it.