[Fred Brackin]

I can contribute a little from personal experience as a surgical patient.

In 2001 when I was talking with my surgeon about the decompressive laminectomy he was planning on my C3-C7 to treat stenosis he gave me The Talk about possible side effects.

It became clear to me that in Gurps terms the final adjusted average for this sort of surgery was 15 or less. 95% success without complications with 5% complications with most of those being less serious (simple failure in Gurps terms) and a few really rather serious complications (Crit Fail in Gurps terms).

So, what modifiers applied? Per Basic there was a -3 for surgery on the head or Chest. Technically this was the cervical spine but I wouldn't make that easier than the head or chest.

Then (per Bio-tech) there was a possible +4 for a Specialized Operating Theater. Bonuses for sssistants with Surgery 12+ were possible but I didn't pay for any so they probably weren't there. I wouldn't count the Anethesiologist as "assisting" the surgeon. He's absolutely necessary but he's also busy doing his own thing.

So if that "average" surgeon has a Skill level of 14 and takes a -3 but then gets a +4 that's a net 15 which is what the average adjusted Skill level for at least that operation appears to be.