Those jobs seem about as equivalent as driver and passenger. You have to focus and avoid risks all day long as a driver. I'm suprised conductor pays more. I imagine they attract different types of people as well -- customer service people vs video game people. Must have been tough epidemiology to tease a signal out of that.
What makes you think that conductor paid more? Certainly nothing that I said!
Likewise what makes you think that the epidemiology was hard? The statistics were absolutely brutally obvious. The main problem was getting people to look at the data, not interpreting it.
