An Educational Diagnostician is a state certification within our Educational Psychology program. It allows me to do individualized assessments such as WISC, Stanford-Binet V, etc. School districts hire Ed Diags all the time to assess special needs students. Few districts, to my knowledge, use them with gifted students. I work independently, generally through referrals from our GT department. They often pass the parents on to me when they don't have an ed diag available. Most often, it is parents who are not happy with the results of the group assessment that their children got at school or when they want "specific proof" of some level of ability in order to request special services for their gifted students.
I'm also an adjunct professor for this online program. You can find out more information about the program at
http://www.coe.unt.edu/educational-psychology/educational-diagnostician
