When people don't do their job properly?

They lack the competency needed to do it 
Solution: Depending on the type of competency, the person may benefit from more training and development. However, many competencies are a function of personality traits that are ingrained and difficult to change even with extensive training. For example, “planning and organizing” is a set of traits and habits that your employee may not have and will be challenged to overcome in a role that requires tracking and pacing their work on month-long project. In many cases, the solution is finding a better job fit for the incumbent’s competencies.