Ian
Perhaps if you got pilots to give you copies of their rosters, flight duties, etc dating back a few years or just gave you a summary of their months work /weeks work . you could comapre the likes of say air berilin and thier national flag carrier, ba short haul easy jet and ryanair , virgin,aer lingus and ba longhaul,emerits, cathy, singapore.
you would need to look at them over a number of years.
would that be of any use to you?
what about if you could say get a member of the public to follow the waking routine and activity pattern of a pilot put them in a decompression chamber, put the pressure to equate to that of an aircraft, similar sights, noise ,vibration levels, give them mental tasks to carry out and see how they feel after a week.
People as passengers on longer flights normally get off the aircraft feeling tired from the inactivity and the aircraft environment just from one flight. They should bear in mind that we get that feeling everyday we fly.