GTA audition tape

[jlh]

I'm applying for an assistantship while I pursue my MM degree and the school requires a videotape (about 45 mins minimum) of me teaching either class piano or private lessons.  I have students and will most likely do the taping next week.  My question is this:

What specifically do the schools look for when reviewing TA audition tapes?  Or, what specifically is being judged?

If anyone has gone through this process before -- either in applying or reviewing the tapes -- I'd love to hear of your experiences.

Thanks!