There are many factors that contribute to the safety rating of an airline including, but not limited to, accident history, maintenance and operational procedures, types of training programs, age of fleet, management, and specific routes flown. In addition, many accidents are caused by circumstances beyond the control of the airline, including, operations and instrumentation at airports, Air Traffic Controller errors, collisions with other aircraft that are at fault, sabotage, manufacturer's design flaws, weather or just plain bad luck. Even if all factors could be factored in, an airline accident is such a rare event that a valid safety rating would be difficult. Accidents are extremely rare, with the probability of a passenger being killed on a single flight at approximately eight million-to-one. If a passenger boarded a flight at random, once a day, everyday, it would be approximately 22,000 years before he or she would be killed.

http://planecrashinfo.com/
From the accident stats & rates:

Now they are hiring "meets minimum qualification" candidates, basically anyone on the ATC list who is willing to take the pay, with special emphasis toward under represented groups, of course.