Thanks to Melphina for the testing:
Forgive me if this is something that was proven long ago, but I've been unable to pull up any data on exactly which stat affects ranged critical hit rate. I asked a member on my linkshell earlier tonight and he referenced a test done on bg a long time ago using thunder staff (simply because no other weapon has dex, not that it affects ranged crit. We all know that thunder staff only affects its own crit hit rate) and stated that dex was tested to be the ranged crit hit stat just like it was to melee. I've always been curious about this but it was never something I could test well enough with my gear at 75, and I didn't feel like running to a zone for a few hours of shooting to try and see.
Well anyway, I've almost built a level 80 Gandiva now and so curiosity got the best of me and I decided to test out what stat boosts ranged crit rate. I chose a setup that made it easy to do.
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The Test
Target Mob == Mamool Ja Lurker (Mamool camp outside the Jade Sepulcher)
Mob Level == 81, 82 or 83
Mob agility == 97
I performed the test with my level 99 thief/dancer
My base dexterity == 113
My base agility == 97
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The test and its results
Parse Data Screenshot
The dex test is actually on the lower half of the screenshot, but I have it labeled appropriately. You can tell which is which by looking at my ranged hit rate as well. The gear changes I made for the AGI test put me at the hit rate cap, but I only had 85% ranged accuracy with my dexterity set.
Part 1: Dexterity Test
My base agility was 97, and the mobs base agility was also 97. Since we had equal base AGI testing for dex was simple. I equipped my twashtar, thunder thokcha, love torque, pixie and hollow, raiders vest and armlets +2, rajas ring, cuchulain belt, athos legs, and rogue's poulaines. I also had to eat a squid sushi because I didn't have my ranged acc set on me and they have a lot of evasion.
My total dex was 113 + 79 == 192 Dexterity.
The only source of agility I had was the squid sushi +1, so I had 97 + 5 == 102 agility.
HYPOTHESIS: Since my dexterity was 90 higher than the mobs agility if dexterity affected ranged critical hit rate I should have a capped ranged critical hit rate of 25% (20% native plus 5% with merits).
The Results:
After I landed 303 ranged attacks my ranged crit rate was only 11.5%. After the first hundred hits were in the percentage never rose beyond 13.5%, and never dipped below 11%. It stabilized over the last 200 hits with only minor fluctuations of. By the last 50 hits the crit rate fluctuated less than 1%, so it wasn't going to change by much after that point.
Conclusion: Dexterity does NOT affect ranged critical hit rate
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Part 2: Agility Test
I didn't have as extensive an agility set on me available to me, but for the AGI test I used ocelo headpiece, arctiers torque, altdorfs and wildhelms earrings, kudzu aketon, alruna's gloves, stormsoul ring, ambushers hose, and athos's boots, and 5 more agi from my sushi.
My total agility was 97 + 77 = 174 AGI
My dexterity was 113 + 26 = 139 (At this point I had already ruled dex out as a possibility, but the total dex I had in part 2 was still 53 less than part 1).
The Results: After 312 hits I had a ranged crit rate of 18.5%. Like the first test, after the first 100 hits the percentages fluctuated mildly, peaking at 19.5% and ebbing at about 18.0%. The final 50 hits mimicked the first test, and the crit rate stabilized at about 18.5%.
Conclusion: Agility DOES affect ranged critical hit rate
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Closing Commentary
Although I significantly boosted my ranged crit rate with +77 agility over mobs agility, I was not at the cap. I can only assume this means that ranged crit rate is a check of player agility versus mobs dexterity. Mamool Lurkers have 97 AGI, but their DEX is unknown. Thieves always have a higher Dex than AGI, and is eaily going to break 100. I ran a very small sample size after the second test with only +67 agility instead of +77 by swapping my athos boots to fajin. I didn't save the parse but after only 70 hits the ranged crit rate was around 13%. That sample size was too small to determine anything conclusively, but it does indicate a probable exponential curve similar to the dexterity curve, wherein +40 agility over mobs dexterity does little and the final 10 dexterity shows a 1% increase in ranged crit rate. That however is just conjecture and should not be taken as anything but a theory without a larger sample size.
Edit: originally the parse link was broken. After noticing that I fixed it and it works now.
Your opionions on this?