The Whole Story

I met a guy yesterday that said, "I did some research online and I found a study that said 12-hour shifts are more dangerous than 8-hour shifts." 

There is a lot of information about safety and productivity on 12's verses 8's.  Here are a couple of examples of complete/incomplete information:

Incomplete: People sleep more on an 8-hour shift than on a 12-hour shift.
Complete:  People on an 8-hour shift sleep about 10 minutes more per night than those on 12-hour shifts. However, both people sleep about an hour more on their days off.  Since 12's have more days off, a person working 12's actually averages more sleep per week than someone on 12's (see Occupational Health and Safety magazine online, March 2008)

Incomplete:  "I saw a study that showed more accidents occur after 8 hours of work."
Complete:  That study showed that people working overtime after putting in a full week have more accidents during that overtime period.  The truth is that 8-hour shifts that cover 24/7, have to rotate (a mathematical fact).  There is overwhelming evidence showing poor safety and poor health on rotating schedules.  There are plenty of studies showing 12's are at least as productive and safe as 8's, even if the 8's were fixed (and therefore not part of a 24/7 coverage).

Incomplete:  "I know a guy that was on a 12-hour schedule.  He died of a heart attack.  Therefore 12's are bad."
Equally Incomplete: "I know a guy that died in his sleep, so sleeping must be bad."

If you have perfect information, then you know 12's are a safe and productive alternative to 8's.  Just as importantly, people that go to a 12-hour schedule have 3 times the schedule satisfaction as those that go to an 8-hour schedule.