Table 2.
Correlations and Validity Estimates for Questionnaire Indicators
| Correlations: Full Sample (Taxon/Complement)
|
||||
|---|---|---|---|---|
| #1/2/7/9 | #3 | #5 | #6 | |
| Symptom #3 | .34 (.27/.22) | |||
| Symptom #5 | .58 (.41/.53) | .28 (.21/.21) | ||
| Symptom #6 | .64 (.48/.53) | .32 (.21/.24) | .46 (.30/.37) | |
| Symptom #8 | .55 (.42/.46) | .23 (.15/.15) | .44 (.26/.39) | .49 (.40/.38) |
| Validity Estimates
|
|||||
|---|---|---|---|---|---|
| #1/2/7/9 | #3 | #5 | #6 | #8 | |
| Taxon M | 0.97 | 0.45 | 0.59 | 0.79 | 0.59 |
| Taxon SD | 0.94 | 1.26 | 0.86 | 0.96 | 0.95 |
| Complement M | −0.35 | −0.16 | −0.22 | −0.29 | −0.22 |
| Complement SD | 0.76 | 0.83 | 0.96 | 0.85 | 0.93 |
| Validity (d) | 1.63 | 0.63 | 0.87 | 1.22 | 0.87 |
| Skew | 0.88 | 1.85 | 0.05 | 0.51 | 0.30 |
Note: MDD = major depressive disorder. N = 1,500; taxon n = 400 MDD+; complement n = 1,100 MDD−. All indicators have been standardized. Symptom numbers refer to DSM-IV criteria for MDD. Indicator validity is expressed as Cohen’s d, the mean difference between the taxon and complement standardized using pooled within-groups variances (weighted by df).