Re: Calculate Interaction Term in SPSS

Posted by Maguin, Eugene on Feb 04, 2011; 2:37pm
URL: http://spssx-discussion.165.s1.nabble.com/Calculate-Interaction-Term-in-SPSS-tp3370327p3371062.html

R,

 

If A, B, and C are highly correlated, you have to assume that you will have collinearity problems. So, you'll need to monitor that in the analysis. That said, I'd center each variable by subtracting it's mean and then simply multiply A*B*C. (As well as A*B, A*C, and B*C). I assume you are doing a regression of some kind so you're final eqation will have seven terms plus the constant (A, B, C, A*B, A*C, B*C, and A*B*C). I would use the centered versions of A, B, and C rather than the raw score versions.

 

Gene Maguin

 

 

 

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From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of R Duke
Sent: Thursday, February 03, 2011 5:46 PM
To: [hidden email]
Subject: Calculate Interaction Term in SPSS

Hello SPSS Experts, 

I apologize for the novice question but I have 3 independent variables (A, B, and C) that are highly correlated and I want to calculate the interaction term for these 3 variables (one DV within). I am new to SPSS and I'm not sure how to calculate the interaction between A*B*C. I have included some mock data below and would appreciate any help. 

Cheers, 

R

0.78	0.62	0.39
0.80	0.98	0.83
0.51	0.42	0.39
0.45	0.60	0.20
0.35	0.53	0.37
0.12	0.58	0.12
0.40	0.43	0.28
0.57	0.84	0.55
0.86	0.68	0.42
0.45	0.21	0.14
0.57	0.53	0.45
0.29	0.37	0.17
0.48	0.81	0.45
0.76	0.44	0.24
0.54	0.62	0.30
0.07	0.06	0.06
0.42	0.92	0.66
0.92	0.91	0.92
0.70	0.76	0.44
1.00	0.25	0.09
0.45	0.45	0.23
0.81	1.00	1.00
0.02	0.53	0.25
0.49	0.91	0.56
0.25	0.58	0.35
0.00	0.00	0.00