Belief that management skill is of primary importance in selecting a manager for an organization, and that domain knowledge is secondary. Or, put another way, it's saferto take a skilled manager from elsewhere and train him in the domain, than to promote someone from within (from a non-management position).
All managers are equally bad?
There is likely some truth to this; some of the worst managers are those who don't have the management aptitude. In years past, when organizations almost always promoted from within, lots of folks got promoted to management who while deserving of a promotion for good work in their previous position, were ill-suited for management (hence the PeterPrinciple). On the other hand, bringing in established managers from elsewhere has its own risks; some managers (who like to call themselves ChangeAgents?) are prone to shuffling the deck without understanding what cards they already hold. Sometimes this can be beneficial to an organization, more often than not it causes lots of disruption, at least in the short term.
OK, here is a different perspective. Rather than ask "who is the best person for this job?", ask, "what is the best job for this person?". Practiced consistently, this becomes selecting appropriate positions for a person through their career with the goal of maximizing individual growth and their contributions to the organization. I think this makes sense for organizations whose primary capital is intellectual. It's not going to work at McDonalds. And it needs people to be clear and honest about what they want to do with their careers - practice and perfect their technical skills, become a technical leader, manage tasks, become CEO. Done well, technical talent will be developed to great depth or breadth as appropriate for the person, new managers will get challenging (but not too challenging) assignments, existing managers will switch between line and project every few years so there will be a lot of sideways movement, work teams will become more persistent than their managers (with all the good things that will lead to), and managers will get wider and less parochial perspectives as they rotate from job to job. Also, it might make it harder for the management antipattern HeirApparent to take root. - Dave Van Buren