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My kid has had 8 standardized tests so far this year. What's the point? Not a single thing has changed based on testing.
Something has changed: data has been gathered and stored. This data may have various uses going forward. Several planed uses have already been announced, but once the data is amassed, it may be used in any number of unforeseen ways as well.

Collected performance data from standardized tests may be used to evaluate teachers. The data may be given or sold to various researchers. It may be used to limit opportunities in high-performing areas in order to achieve uniform outcomes desired by common core. The data may be used against your child in future attempts at advanced education and/or career choices and/or specific jobs.

A general sketch of data collection requirements may be seen at the links in this old post.

Families have reported difficulty in accessing and correcting/amending their children's data. Inability of parents to see and/or correct the data stored on their children has been covered in several news stories, including
1) http://www.foxnews.com/us/2014/05/13/price-for-nevada-dad-to-see-state-school-files-on-children-10g/
2) http://nevadajournal.com/2014/04/24/dad-told-seeing-states-records-his-kids-will-cost-him-10-grand/.