What are the effects of having a long test window?

Document created by Community User on Aug 4, 2017Last modified by Community User on Apr 17, 2019
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Is there a negative effect on RIT scores if a test window is open longer than three weeks?

A long test window does not affect the RIT scores produced, but there could be implications for how the growth norms are applied.
Growth measurements assume that a specific number of weeks of instruction occur between the two comparison terms, such as fall to spring. You can configure the number of weeks of instruction before testing. See How to modify instructional weeks.
If you have a long test window, some students will have significantly more or less weeks of instruction than others, impacting the accuracy of their growth projections. When the difference of instructional weeks is only off by 1 to 3 weeks, it won’t have much impact. If the difference is more than 3 or 4 weeks, then it will start to have measurable impact.
NWEA recommends test windows be shorter than three weeks, and be consistent year over year in order to generate the most reliable growth projections.

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