# Comparing results of two different tests measuring correlational relationship?

#### morepil

##### Member
Hear this.
I have three scales Scale A, B, and C.
I want to compare the strength of relationship between Scale A and B, and between Scale B and C.
Details:
Scale A: Actually, this is not a scale. This is just 1 question with 4 nominal answers. What type of family do you have? Authoritarian, democratic, inconsistent, undefinable.
Scale B: RWA scale. Scores between 0-160. Lower the better. No decimals.
Scale C: CTQ Scale. Scores between 0 100. Lower the better. No decimals.
Can this be done; is this legitimate comparing coefficients from two different types of tests? Are they even two different tests or are they just basic correlation spearmen etc.?

#### j58

##### Active Member
For A vs B, I think I would regress B (DV) on A (coded as dummy variables (IVs)). This would provide R^2, the proportion of the variation in B explained by A.
For B vs C, you can compute the Pearson correlation. If comparability with the above is desired, square it.

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#### morepil

##### Member
Thanks for the response. So I can use liner regression for the first one and Spearman correlation for the second one. And when I square the Spearman's coefficient, I'll be able to compare the strength of relationship between the two. But.. Spearman correlation is noted by
(rho).

#### j58

##### Active Member
The square of the sample Pearson correlation coefficient, r, is equal to the proportion of the variability in one of variable explained by the other. If you don't believe this, calculate the correlation between B and C, then regress B on C, and compare the two r^2 values.

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#### j58

##### Active Member
You were right to not believe me! I meant the Pearson correlation. I've corrected my posts accordingly.

#### morepil

##### Member
Oh Ok. I just wanted to make sure I understood correctly due to english not being my native language..
Best..

#### morepil

##### Member
Hi its me on this particular message again.
Can you elaborate on how to find the r^2 on the relationship between A and B. Coding A as a dummy variable, how?
Many Thanks.

#### j58

##### Active Member
I assume you're using statistical software to do your analysis. If you regress B on A (coded as dummy variables), your software should report R^2.