What can we do to ensure that staff are continually provided information on their roles and responsibilities?

One of the things most organizations struggle with is ensuring compliance; especially if you take into consideration the human factor. For example, my office always asks the workforce specific questions on their knowledge and responsibilities; but what we find is that some know and some do not know what their responsibilities are. While they may have everything else in place, ensuring staff are doing the right thing may never occur. What can we do to ensure that staff are continually provided information on their roles and responsibilities?