Certification- Is it Really Value Added?

It seems certification of one kind of another has become a growth industry. My question and thought; is it really improving the quality of practitioner and services to clients? I look at it particularly in two arenas I feel somewhat comfortable in talking about- Coaching and Human Resources.
Both of these fields have much to do with interpersonal interactions and effectiveness. In particular the human resources field has disciplines and dimensions that are quite technical and compliance oriented. These areas require training and skills development.
I look at other areas and say that the ability to pass an examination does not guarantee the ability to communicate and build effective relationships.
I would say the same for "coaching". I think there are tools and processes and techniques to identify certain styles and development needs of people and organizations, but is that the complete picture?
Does a law degree and being admitted to the bar make you an effective counselor or litigator? Does an MBA really prepare you to lead an organization?
We write and study and discuss effective management and "leadership" ad nauseum. Does certification teach those skills or attributes?
I believe you can certify "competency" the achievement of completing a course of study, but that is not the same as effectiveness. What do you think? Should we use "certification" as a screen in non licensed professions?