Here's what I propose we should do to figure out the causality 1. Split Microsoft into three parts, each with its own exactly equivalent market. 2. Have Satya

Here's what I propose we should do to figure out the causality 1. Split Microsoft into three parts, each with its own exactly equivalent market. 2. Have Satya Nadella as the CEO of one of them, Steve Ballmer as the CEO of the other, and a control group with no CEO in the third. The lift obtained from the first may be because of Satya Nadella. It's possible that Steve Ballmer may be getting worse over time, which is why you have a third control buckets to compare against.