I would say human factors since long term dedication is much more likely if the employees are treated like human beings by someone with a genuine interest in their lives and concerns and also by someone who is considerate ie by giving time off for compassionate reasons etc. I worked at a large open pit copper mine where the employees were treated often with contempt and at times as if they were slaves, especially the hourly employees in what I would call a British colonial manner and in the end they had a lengthy strike against the company and part of their demands were human rights to be treated with respect.