Table 4.

Logistic Regression Analyses Testing Incremental Validity for Assessment of Marijuana Use

	All Participants (n = 983)				White Participants (n=669)				Black Participants (n=271)
Step 1	Model fit χ2(2) = 176.98***, R2 = 0.41				Model fit χ2(2) = 143.77***, R2 = 0.50				Model fit χ2(2) = 31.68***, R2 = 0.26
	β	S.E.	Odds Ratio	Odds Ratio 95% CI	β	S.E.	Odds Ratio	Odds Ratio 95% CI	β	S.E.	Odds Ratio	Odds Ratio 95% CI
Self-Report	3.73***	0.35	41.69	21.19–82.02	4.73***	0.61	113.74	34.22–378.03	2.65***	0.50	14.12	5.32–37.50
Step 2	Model fit χ2(4) = 203.47***, R2 = 0.46 Δ χ2(2) = 26.49***				Model fit χ2(4) = 158.16***, R2 = 0.55 Δ χ2(2) = 14.39***				Model fit χ2(4) = 36.92***, R2 = 0.30 Δ χ2(2) = 5.23
	β	S.E.	Odds Ratio	Odds Ratio 95% CI	β	S.E.	Odds Ratio	Odds Ratio 95% CI	β	S.E.	Odds Ratio	Odds Ratio 95% CI
Self-Report	3.02***	0.38	20.43	9.76–42.79	3.97***	0.65	52.72	14.69–189.18	2.29***	0.53	9.90	3.52–27.83
Urine	1.29***	0.35	3.63	1.82–7.23	1.06*	0.44	2.89	1.22–6.83	1.15	0.63	3.16	0.92–10.90
Hair	0.68*	0.34	1.97	1.01–3.85	0.81	0.44	2.25	0.95–5.31	0.36	0.57	1.44	0.47–4.37

Notes.

^*P < .05.

^**P < .01.

^***P < .001.

R² values are Nagelkerke.