This is actually more than one tip and again this tip of the day came to me as I was reviewing a file and after speaking with an assessor last week. In this case, the Parent had requested an IEE and the District provided a list of names and the Parent picked one and the assessment was completed.
The problems started, however, when the District sent the assessor the "file" which was only a few pages of an IEP. Which brings us to the first tip:
Even if the District is paying for the assessment and has told you they will provide the assessor the file - bring all relevant paperwork with you and leave them with copies.
The next problem occurred because the assessor was not invited to the IEP. Now under the law so long as there is someone there qualified to review the assessment findings the assessor does not need to be there but tip #2:
Always at least REQUEST (in writing, of course) that the independent assessor be invited to the meeting to review their assessment.
They may say "no" but then you're in the same position as before but now if you have a question at the meeting that the district personnel can't answer you have a reason to ask for another IEP.