Bloodborne Discovery and Drop Quality Analysis

Bloodborne Discovery and Drop Quality Analysis by jdfred06

One of the current hot topics within the community (other than shoddy matchmaking) centers around the limited availability of upgrade materials, namely blood chunks and blood rocks. It’s well known that chunks do drop from certain enemies (Blue Eyed Werewolves and Gargoyles specifically), and many people have made statements or have provided anecdotal evidence that the Discovery stat has an effect not only on drop occurrence, but also drop quality (usually by suggesting the Eye Rune(s) increased drop rates). However the overall community seems mixed on this, as some posit it does in fact help drop quality, others saying it has no effect at all. This post is designed to approach this question in an unbiased and pragmatic way.


I ran the Upper Cathedral Ward 24 total times and killed the 4 Werewolves on the bottom floor. For the sake of time, I opted not to get the one on the second floor. 12 of these runs I didn’t run any discovery boosting runes (Eye runes), and the other 12 I ran the 3 Eye Runes. This allows for a total sample of 96 enemy drops, 48 for each sample group. I think this is an adequate sample size to simply test for mean/proportion differences. Given the results, it’s not as big of a deal either. update Now we have data for drops at 100 Discovery. The results do not change.

I will go into this assuming that Discovery has no effect on quality, and will stand in as my null hypothesis. The alternative is that Discovery does in fact affect drop quality.

Character Stats :

  • Lvl: 220
  • Arcane: 50
  • Insight (just in case) : 38
  • Discovery: 206
  • Discovery with Eye Runes : 420

As you can see, this is a significant difference in the Discovery stat, hopefully enough to give us a large enough variation to determine the overall effect. edit Now I’ve included the drop rate at 100 discovery.


I’ve uploaded a Google Doc with my drop information. The Werewolves dropped the following items (in descending probability):

  • Bone Shards
  • Twin Bone Shards
  • Blood Chunks
  • Blue Elixirs

Google Doc can be found here:

The end result is that I have found literally no evidence that Discovery has any effect whatsoever on drop quality, as the average drop rate with and without Eye Runes is EXACTLY THE SAME, at 12.5% per enemy drop. I was actually surprised that there was no difference at all (save for Elixir drops), as I had originally planned to test for significant differences. This isn’t conclusive evidence that there isn’t a difference at all, but it’s pretty damning if you’re trying to prove the original hypothesis that Discovery affects Drop Quality, as this is evidence to the contrary.

These results lead me to believe that Discovery alone has no significant positive effect on drop quality. If the sample means/proportions were different, I would test the significance of the differences, but in this case it would be useless.


I make a few assumptions in my testing. The first assumption is that Discovery scales linearly, with no diminishing returns. The second assumption is that each run is independent of another (this is a very relaxed assumption, however). And finally, I assume that no other stat affects drop quality and/or rate. The first two assumptions are almost made moot given the results for each run type are identical, and the final assumption is controlled for in that the only stat that changes is the Discovery stat.

That’s all I have. Hope you guys can get some use out of this, and Happy Hunting!

TL;DR – Don’t run Eye Runes if you’re looking for Blood chunks.

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