A written exam indicates whether a technician has retained the knowledge to be competent, but not whether they are competent. Just as new drivers take a written exam and a road test to demonstrate their knowledge and skill, Master Specialists are required to go beyond a written test and demonstrate their skill and workmanship. The analogy would be knowing which solder to use and then demonstrating that you can solder tubing that is structurally sound and leak free. The Master Specialist program requires a technician to demonstrate retained knowledge and prove that they can apply that knowledge through skill verification.
HVAC Master Specialist Website