[erydo]

Devil's advocate: Wouldn't a person who prefers sitting be more likely to keep a job as a driver rather than conductor?

An unhealthy person might think, "Ugh, I'd have to be on my feet all day." And a healthy person may not see that as a major negative.

[marknutter]

Not everyone can be so choosey about the job they get

[dllthomas]

But some can, and maybe it's enough to impact the study. Or maybe not.