Question:  I remember some time ago hearing that an assessment cannot be opened either before or after the ARD window, only during.  Is this true?  

Answer: The requirement in the RAI User’s Manual limits the ARD selection to no later than by midnight of the end of the ARD window. It does not put a limit on how early you open an assessment.

The point that could be challenged would be how you would know that a particular ARD is the best ARD to select, the further you are from that date when you select it.

Please also keep in mind that for the unscheduled OMRA assessments (COT, EOT, or SOT) there is a very short ARD window.  Proper planning should be in place so that these assessments are opened timely. It may be very risky to wait until the ARD window to open these assessment types.