If you aren't serious about the candidate...Don't bother!

Too often internal interviews are done out of courtesy or because of protocol. Interviews should not be a waste of anyone's time. Prior experience and job performance are the most important criterion in predicting future performance. If the applicant is not a true candidate for the job, do not interview them. This is especially true with internal applicants.

However, if you are the employees’ direct supervisor and they are not qualified for the job yet you need to have a conversation with your employee. This will help them understand what they need to do to move up the ladder and also keep them engaged and not feeling overlooked. So the next time a position opens they will (hopefully) be ready for the promotion. Keep in mind that internal candidates are likely to be around after the search process is over. It is important to treat them with respect, which includes not leading them on and being honest about their suitability for a job. This is sometimes a difficult discussion however, it will open up the doors for communication and growth. Your team will respect you for it!

If you are not willing to have these discussion then you need to rethink your role because, a manager needs to be a leader. Leaders help their people grow and excel!