Thinking out loud, I would think that even if a parent DID consent, such consent could be revoked at any time, especially in a situation where continued participation would so obviously hinder the child's education.
I'd want to (a) find out from the Gates Foundation the precise parameters of the study and consent, and (b) I think you're right to give the principal another chance here (I think you're correct that she's probably just using the study as an excuse), though I can't say I'd want to wait a week (when is your appt? if it's not until late next week I'd try to get in with her today; if it's Monday, I'd wait and take the time to arm myself with...whatever I could find).
Are there kids in the school whose parents did not consent? Is this a regular neighborhood elementary school, or some other special type of school?
Last edited by snowgirl; 09/23/10 09:06 AM.