Table 4. Screening Properties for CTA Risk Factor Combinations.

Risk factor combination / Logical operator rule	Sens- itivity	Spec- ificity	PPV	NPV	Positive screen	Overall accuracy
Depressive symptoms and/or poor school functioning
“And” rule	.53	.85	.35	.93	.20	.81
“Or” rule	.79	.58	.22	.95	.47	.61
Depressive symptoms and/or low parental support
“And” rule	.42	.91	.30	.86	.18	.80
“Or” rule	.87	.55	.22	.97	.51	.59
Poor school functioning and/or low parental support
“And” rule	.37	.85	.26	.90	.18	.78
“Or” rule	.89	.52	.22	.97	.53	.57
Depressive symptoms and/or poor school functioning and/or low parental support
“And” rule	.32	.90	.33	.90	.13	.84
“Or” rule	.94	.45	.20	.98	.60	.51

Note. CTA = Classification Tree Analysis; PPV = positive predictive value; NPV = negative predictive value; Positive screen = proportion of sample screened positive; Overall accuracy = proportion of sample correctly classified. The “and” rule specifies that all of the risk factors in the combination are present to screen positive; the “or” rule specifies that any of the risk factors in the combination are present to screen positive.