Decision Between Multiple Regression and Canonical Correlation

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Decision Between Multiple Regression and Canonical Correlation

bdates
I'm assisting a colleague with a study of the relationship of ethnic identity and traditionality-modernity to acculturation. Acculturation is the dependent variable. The scores used in prior research include two subscales - traditionality and modernity; and a full scale acculturation score, which is determined by modernity minus traditionality. Not at all surprising is the fact that while the two subscales have a very low correlation, they both correlate highly to the overall acculturation score. So, because of the colinearity aspect, I'm concerned about including them all as possible DV's in a canonical regression analysis. If parsimony is an issue, then I could simply use the overall score and do a multiple regression. I'm also aware that selection of scales to use based on colinearity is discussed only for IV's. So...my moderately informed opinion is to go with the two subcales in the canonical correlation analysis. Thanks for any input.

Brian
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Re: Decision Between Multiple Regression and Canonical Correlation

Rich Ulrich
Canonical gives you a test for "any combination of the IVs" as criterion.
Is that useful for you?

If you have oodles of excess power, then the canonical correlation
is fine for an overall test.  Coefficients will show you if the first root
is similar to the Acculturation Score -- which you are then justified in
analyzing as a follow-up -- and you also have the possibility of defining
a second root.

Obviously, a regression with one DV is more powerful than having two.
Do you have enough power so that your regression would be powerful,
even if it had twice the IVs as what you have? - That is a crude guess
at how much power is lost by using 2 d.f.  for an outcome rather than one.

If power is a problem and you don't mind missing the wider test, then
you want the single regression

Besides power, the other thing that you gain from a regression is a clear
statement of "Acculturation" as a criterion for your hypothesis.  Is that
something you want?

The main thing that you get from the two DVs being /highly/  correlated
(when they are) is that it might be clearer to the Investigator on a-priori
grounds whether a composite outcome is expected:  whether that is the
sum or the difference score.

--
Rich Ulrich


 

Date: Wed, 14 Oct 2015 22:04:02 +0000
From: [hidden email]
Subject: Decision Between Multiple Regression and Canonical Correlation
To: [hidden email]

I'm assisting a colleague with a study of the relationship of ethnic identity and traditionality-modernity to acculturation. Acculturation is the dependent variable. The scores used in prior research include two subscales - traditionality and modernity; and a full scale acculturation score, which is determined by modernity minus traditionality. Not at all surprising is the fact that while the two subscales have a very low correlation, they both correlate highly to the overall acculturation score. So, because of the colinearity aspect, I'm concerned about including them all as possible DV's in a canonical regression analysis. If parsimony is an issue, then I could simply use the overall score and do a multiple regression. I'm also aware that selection of scales to use based on colinearity is discussed only for IV's. So...my moderately informed opinion is to go with the two subcales in the canonical correlation analysis. Thanks for any input.

Brian
===================== To manage your subscription to SPSSX-L, send a message to [hidden email] (not to SPSSX-L), with no body text except the command. To leave the list, send the command SIGNOFF SPSSX-L For a list of commands to manage subscriptions, send the command INFO REFCARD
===================== To manage your subscription to SPSSX-L, send a message to [hidden email] (not to SPSSX-L), with no body text except the command. To leave the list, send the command SIGNOFF SPSSX-L For a list of commands to manage subscriptions, send the command INFO REFCARD
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Re: Decision Between Multiple Regression and Canonical Correlation

bdates

Thanks, Rich. I’m going with the multiple regression because I don’t have enough power with the canonical. One of the tests has been revised, which I found out after I sent my message yesterday. The revision has correlations between the two subscales and among the two subscales an total score greater than .95, and the VIF’s are all above 5. It’s the same for the intercorrelations among the three possible dependent variables, so I went with one DV. Thanks again, Rich.

 

Brian

 

Brian Dates, M.A.
Director of Evaluation and Research | Evaluation & Research | Southwest Counseling Solutions
Southwest Solutions
1906 25th Street, Detroit, MI 48216
313-297-1391 office | 313-849-2702 fax
[hidden email] | www.swsol.org

 

From: Rich Ulrich [mailto:[hidden email]]
Sent: Wednesday, October 14, 2015 8:17 PM
To: Dates, Brian; SPSS list
Subject: RE: Decision Between Multiple Regression and Canonical Correlation

 

Canonical gives you a test for "any combination of the IVs" as criterion.
Is that useful for you?

If you have oodles of excess power, then the canonical correlation
is fine for an overall test.  Coefficients will show you if the first root
is similar to the Acculturation Score -- which you are then justified in
analyzing as a follow-up -- and you also have the possibility of defining
a second root.

Obviously, a regression with one DV is more powerful than having two.
Do you have enough power so that your regression would be powerful,
even if it had twice the IVs as what you have? - That is a crude guess
at how much power is lost by using 2 d.f.  for an outcome rather than one.

If power is a problem and you don't mind missing the wider test, then
you want the single regression

Besides power, the other thing that you gain from a regression is a clear
statement of "Acculturation" as a criterion for your hypothesis.  Is that
something you want?

The main thing that you get from the two DVs being /highly/  correlated
(when they are) is that it might be clearer to the Investigator on a-priori
grounds whether a composite outcome is expected:  whether that is the
sum or the difference score.

--
Rich Ulrich


 


Date: Wed, 14 Oct 2015 22:04:02 +0000
From: [hidden email]
Subject: Decision Between Multiple Regression and Canonical Correlation
To: [hidden email]

I'm assisting a colleague with a study of the relationship of ethnic identity and traditionality-modernity to acculturation. Acculturation is the dependent variable. The scores used in prior research include two subscales - traditionality and modernity; and a full scale acculturation score, which is determined by modernity minus traditionality. Not at all surprising is the fact that while the two subscales have a very low correlation, they both correlate highly to the overall acculturation score. So, because of the colinearity aspect, I'm concerned about including them all as possible DV's in a canonical regression analysis. If parsimony is an issue, then I could simply use the overall score and do a multiple regression. I'm also aware that selection of scales to use based on colinearity is discussed only for IV's. So...my moderately informed opinion is to go with the two subcales in the canonical correlation analysis. Thanks for any input.

 

Brian

===================== To manage your subscription to SPSSX-L, send a message to [hidden email] (not to SPSSX-L), with no body text except the command. To leave the list, send the command SIGNOFF SPSSX-L For a list of commands to manage subscriptions, send the command INFO REFCARD

===================== To manage your subscription to SPSSX-L, send a message to [hidden email] (not to SPSSX-L), with no body text except the command. To leave the list, send the command SIGNOFF SPSSX-L For a list of commands to manage subscriptions, send the command INFO REFCARD