Surgery Success Chance

[TheClassiness]

I have a colonist who needs a bionic eye installed. I made sure to assign my best surgeon, using a hospital bed, vitals monitor, sanitary tiles (with no dirtiness), and the doctor has full needs (unsure if this affects it). With a whopping success chance of 102%, he manages to decapitate the patient. I am unsure if I am simply misreading something, or if there's other factors in play, but this seems a bit excessive none the less. Almost makes any kind of surgery a death sentence.

[nccvoyager]

Indeed, this seems strange to me as well.
A 100% or greater "success chance" for surgery should mean no failures, right?
Or, at least, it should mean no major failures, I would think.

Are there other factors in play that are not shown to us, the players?

[Ark]

Medicine effectiveness was nerfed massively in A16. What kind of medicine did you use?
Head area surgery is very dangerous, since even a minor failure means jabbing the scalpel into the brain.
I would only do those with glitterworld medicine.

Code Select Expand


A15 A16
No Medicine 50% 20%
Herbal Medicine 75% 40%
Medicine 100% 70%
Glitterworld Medicine 160% 160%


[nccvoyager]

Okay, this is good information to know.

I wonder if it would be possible for the addition of a method of determining the overall chance of surgery success, including medicine quality.
This would help reduce frustration on the part of players using the "surgery success chance" stat to choose their best doctor, and remove confusion regarding failed surgeries with doctors with a greater than 100% surgery success chance.

Perhaps something as small as adding visible medicine surgery success modifiers to the advanced information section of the surgery success chance stat?
Couple that with making the stat default to success rate with standard medicine, and all confusion would be removed.
(Though, "surgery success chance with standard medicine" is a little too long for the information panel. Not sure of a workaround there.)

Thank you for letting us know about this.
I knew that medicine types carried modifiers for surgery success, but I hadn't realize they had changed.

[Calahan]

As Ark says, there were quite a few changes (nerfs) to surgery/medicine in A16, which has resulted in considerably reduced success chances. Tynan has posted on Reddit to say that there is going to be more changes to this again in A17 as currently "It's all messed up in a lot of ways". Here is a link to Tynan's Reddit comments.
https://www.reddit.com/r/RimWorld/comments/5ns36b/i_still_dont_understand_the_surgery_probabilities/dce2t0e/

I will close this now as a known/resolved issue. Although thank you for taking the time to report it all the same.