I agree with your points about high school completion and college enrollment, however I think the reason for the increased difficulty of getting into a school is due to increased competition rather than an increase in absolute standards. A way to test this would be to look at the history of schools that use admissions tests. (I'm thinking of elaborate tests such as at Cal-Tech.)
> The data dont show consistend decline in years where it did not changes, but there are massive drops in scores when the test was recalibrated.
I'm a bit confused about what you are referring to, but I think that by "recalibrated" you are referring to 2011 when they introduced the revised scale. I think I can clear this up by explaining about standardized testing.
The purpose of the GRE, SAT, and some other tests created by the Educational Testing Service is not to measure absolute performance of individuals but relative performance of populations. The goal of test design is to adjust the difficulty of the test to provide maximal discrimination in the tails. So when the average performance of a population changes, they have to adjust the difficulty of the test to keep the results curve in a nice shape. This is what I meant by "recalibration". If they achieve their goals in this, average scores shouldn't change much over the years.
> The data dont show consistend decline in years where it did not changes, but there are massive drops in scores when the test was recalibrated.
I'm a bit confused about what you are referring to, but I think that by "recalibrated" you are referring to 2011 when they introduced the revised scale. I think I can clear this up by explaining about standardized testing.
The purpose of the GRE, SAT, and some other tests created by the Educational Testing Service is not to measure absolute performance of individuals but relative performance of populations. The goal of test design is to adjust the difficulty of the test to provide maximal discrimination in the tails. So when the average performance of a population changes, they have to adjust the difficulty of the test to keep the results curve in a nice shape. This is what I meant by "recalibration". If they achieve their goals in this, average scores shouldn't change much over the years.