Sometimes the best way to transfer knowledge is through games rather than tests.
This can be used at home with your children or at work.
For my child, if he asked a question (something he learned or is curious about) and I knew the answer, then he gets one point (free throw).
If he asks me a question that I did not know the answer and he does or is able to obtain the answer through research, then he gets two points (field goal).
If he asks a question in school, then he gets a three points (three pointer).
When he accumulates 100 points, he gets a $10 iTunes card.
This can be easily replicated at work with work related questions. You can enable knowledge transfer through a game without anyone feeling like they are being tested.
Try it and see if it helps.
A good blog to read about questioning is the one I read in Harvard Business Review titled, "The Art of Asking Questions."