The Importance of Correlation in Test Theory

A measure of musical pitch discrimination is only a score that itself isn't a perfect measure of your pitch discrimination. That's the foundation of classical test theory, the idea that any score that you hold is part truth and part error with respect to the measurement of the thing itself. And as a result of that, we have to try to navigate this world where we are correlating things that in and of themselves are not the actual things that we care about.