Concerns with Action Research Plan

I have several concerns with the action research plan that I have developed.  These may or may not be legitimate.  First, I'm concerned that it will be difficult to measure the actual effect of Ipod implementation on student progress because of all of the other factors involved.  These include a new curriculum (C-Scope) as well as teacher efficacy, both of which could produce positive results regardless of the technology used.  Second, much of the evidence will be anecdotal from surveys and interviews.  I'm wondering how this will effect results.  I know that, in the Dana text, Leading with Passion and Knowledge: The Principal as Action Researcher, anecdotal evidence is considered valid.  I just want to be sure that the evidence that I gather  shows evidence of the effectiveness of the implementation of IPods in Science classes.  Finally, effectiveness of Ipods in classes may be affected by the manner in which teachers implement the technology.  As the researcher, I feel that I have to, as much as possible, ensure that teachers are implementing the technology with fidelity.  I have tried to include this in the plan through training, which was already scheduled, as well as opportunity for mutual teacher support in the process.  In a nutshell, this a new journey and I want to be sure, as much as possible, that the plan is laid out effectively and will reflect the actual results of the technology.