Why aren't people management practices keeping up with what science knows works?

What works when it comes to the leadership and management of today's teams is no mystery - there is plenty of scientific research providing evidence of what is effective.  

Why then, are poor management practices, and correspondingly low levels of employee engagement, so rampant?  

It saddens and frustrates me to think of all the lost potential, the squandered confidence and untapped talents of millions, if not billions, of people working around the world due to this phenomenon.

From traditional mediums such as books and training courses to online platforms like TED and Coursera, there is no shortage of ways (many of which are free or low cost) to educate oneself in what works.

How much do you know about the modern science of effectively managing people?  Test your knowledge using the quiz below.