Currently using leaderboard data from Level 100, which is still relevant when evaluating what is effective at 110. Statistics will be updated using level 110 players when Legion matures and more players are playing competitively in PvP at 110.
Shadow Priest PvP Stat Priority - 7.0.3
The below Stat Priority recommendation is automatically generated through statistics from the best Shadow Priest players in competitive PvP, updated frequently. Use this guide for insight on what stats the most successful PvP Shadow Priest players are currently focusing on.
Mastery > Versatility >= Haste > Crit
Primary stats such as Stamina and Intellect are not included in priority as it is difficult to determine the value of them through analyzing data from PvP leaderboards. However, knowing the value of secondary stats is highly usable as the majority of enchants, gems, consumables and gear stat differentiations are focused on secondary stats.
With that being said, Intellect is very powerful and perchance rivals or surpasses the value of Mastery in PvP.
62.28% of the top PvP players focus on Mastery.
Mastery provides a passive bonus to your character based on your specialization. Mastery Madness increases the damage done by Shadow Word Pain, Vampiric Touch, and Void Bolt.
18.05% of the top PvP players focus on Versatility.
Versatility increases your damage, healing, and absorption done and decreases damage received.
15.46% of the top PvP players focus on Haste.
Haste increases attack and spell casting speed, adds additional damage and healing to DoTsA spell or ability that does damage over time. and HoTsA spell or ability that heals over time., and reduces the GCDA universal cooldown activated by most abilities..
4.21% of the top PvP players focus on Crit.
Critical Strike increase the chance for your spells and attacks to critically hit for additional damage and healing.
Intellect increases the damage and healing done by your spells.
Stamina increases your total health.