Why do we have to rely on operational definitions to study ...

[big1devin]

Why do we have to rely on operational definitions to study abstract hypothetical constructs?
 
  What will be an ideal response?

Question 2

What is the difference between the Pearson r, the Spearman correlation for ranks, and the phi coefficient? How are they similar?
 
  What will be an ideal response?

[bookworm410]

Answer to Question 1

Abstract hypothetical constructs are hard to characterize because they are not concrete. So we have to find out some objective way to measure them. Any measurement we choose is not going to be exactly the same as the underlying concept, but we need that measurement to represent the hard-to-define idea we want to deal with.

Answer to Question 2

These four tests are mathematically equivalent. You can use the standard formula for the Pearson r for them all, regardless of scale of measurement. The difference among them is that when you have

[big1devin]

Thanks for the timely response, appreciate it

[brbarasa]

Excellent