standardized odds ratio interpretation

Posted by Greg on Jun 23, 2016; 5:42pm
URL: http://spssx-discussion.165.s1.nabble.com/standardized-odds-ratio-interpretation-tp5732518.html

I was hoping to get some clarification in terms of interpreting a set of standardized odds ratios (which SPSS calculated while running binary logistic regression). The following is a small hypothetical example of the results ( I will post the unstandardized and standardized results.)

Unstandardized results

                  beta      odds ratio
Group A:   -1.149     0.317
Group B:   -0.839     0.432
Group C:   -1.340     0.262
(group d reference group)
(dependent variable is binary: 1: happy/ 0: not happy

Standardized results

                  beta      odds ratio
Group A:   -0.433     0.648
Group B:   -0.339     0.713
Group C:   -0.119     0.888
(group d reference group)
(dependent variable is binary: 1: happy/ 0: not happy

Based on the unstandardized results, the odds of being happy for group C are 73.8% lower than those of group b (56.8%). Therefore, group b has higher odds of being happy than the odds of group c.

Based on the standardized results, the odds of being happy for group C are 11.2% lower than those of group b (28.7%). Therefore, group c has higher odds of being happy than the odds of group b. (I understand that this refers to standard deviation units.)

Is the above correct? This is the first time I'm using standardized odds ratios.

Also, the odds ratio (in terms of absolute numbers) for Group c is the lowest in the unstandardized version, but the highest in the standardized. Is this normal? (based on the hypothetical example I provided).

Thank you in advance for your help!