> Except 1) those tests weren't designed for that purpose

I don't know if that's true. And even if it were, why would they need to be designed for that purpose to be successfully and correctly used for that purpose? In fact, at one time the federal government required this data to be provided by schools. However, the teacher's unions lobbied hard, and the 2015 "Every Student Succeeds Act" barred the government from requiring this data: https://www.edweek.org/policy-politics/essa-loosens-reins-on...

"But the teachers’ unions see an opening to change policies their members have broadly rejected. They are also far more powerful among state legislatures than in Congress."

"The American Federation of Teachers plans to bring its political clout to bear on the issue, too."

On the other hand, strong research exist to show that SGPs are a valid and useful measurement: https://pubs.aeaweb.org/doi/pdfplus/10.1257/aer.104.9.2593

"The main lesson of this study is that value-added models which control for a student’s prior-year test scores provide unbiased forecasts of teachers’ causal impacts on student achievement. Because the dispersion in teacher effects is substantial, this result implies that improvements in teacher quality can raise students’ test scores significantly."

And the follow-up study: https://pubs.aeaweb.org/doi/pdfplus/10.1257/aer.104.9.2633

"This paper has shown that the same VA measures are also an informative proxy for teachers’ long-term impacts."

> 2) they are a worse measure of student preparedness than GPAs

GPAs are highly subjective, and more importantly, harder to compare across schools and even across classes. By using standardized scores, for instance, one could track successfully that a teacher's performance remains consistent as he or she moves across schools. Remember, this was about measuring teacher performance, not student performance. That said, if GPAs really were better for teacher evaluation, there is nothing stopping you from measuring student GPA improvement instead of student standardized test score improvement, so I'm not sure what you're really arguing against at this point.

> 3) they only test those topics which are easy to test in a standardized setting.

Many important topics taught in secondary school are well-understood and amenable to standardized testing, including: math, reading comprehension, grammar, some aspects of science and history, etc.

> Since you think peer review is important, why do you point to non-peer-reviewed sources?

These books cite peer-reviewed sources and are a great starting point before digging further.

> Just looking at the authors shows that I expect them to have a pro-standardized testing viewpoint.

Everyone is biased. The NEA spends millions convincing people to drop standardized tests through their advocacy group, FairTest, which serves as one of their front organizations. Much of education academia is biased against standardized testing. Biases are everywhere, and were fairly obviously present in your sources that I checked. At some point, you have to pick a bias you trust more, and I trust the bias that says standardized tests are useful over the bias that says they should be entirely done away with.