What to do when you don't agree with your stakeholder's requests

When I attended the ISPI Principles and Practices of Performance Improvement three-day workshop last year, I remember a story that Miki Lane told. He was a young performance consultant when a company called him up and asked him to lead a team-building training. He said, "Yes, I am happy to help." He conducted a brief analysis and discovered that, in his opinion, this team did not need a team-building training. He recommended several alternative performance interventions. His client did not want to hear his ideas and did not hire Miki as a consultant. A few weeks later, he saw a news clip about ABC company taking their team on a team-building trip in the woods. 

This story has remained with me for over a year and seems particularly relevant in my current situation. It illustrates an example of when a stakeholder calls you up, knows exactly what solution they want, and doesn't want to listen to any alternative solutions. 

In my current situation, a key stakeholder has decided that he wants to implement a certification program that includes a difficult SAT-like examination. I am firmly opposed to any multiple-choice tests in the workplace (a topic for another day)! I do not believe they accurately measure performance. Since the vast majority of performance problems result from environmental problems (like a lack of clear expectations and feedback, inadequate tools and compensation models), why does it make sense to test people? 

The test will be used not only to assess individual's skill gaps but also to identify gaps in training offerings. It seems to me that if we have to create this test, we should create learning solutions from which people can study first. I am concerned about the self-esteem (or worse, employment) issues that may result from people "failing" the test. I am worried that it will be a waste of time because we do not have a clear plan of what we'll do with the data or how to communicate scores and gaps to the learners. 

And yet, the stakeholder says we must do it, so we will.