By Using Instrumental Variables,what Was Ramanarayanan Able to Suggest Regarding

Multiple Choice

By using instrumental variables,what was Ramanarayanan able to suggest regarding the learning curve?

A) High quality surgeons receive more referrals and can be choosier with their patients thus experiencing better outcomes
B) Surgeons who treat more patients after the retirement of a colleague experience better outcomes
C) Surgeons who treat more patients after the retirement of a colleague experience the same outcomes
D) Surgeons who treat more patients after the retirement of a colleague experience worse outcomes
E) Each additional surgery performed by a surgeon increases the probability of patient mortality