Table 3.

Effectiveness results, continuous patient outcomes

Measures		Sample size	Baseline	6 months	Za,b (P value)	Effect size db,c
		N	Mean (SD)	Mean (SD)
Substance use in last 30 days
	Any drinking days	207	2.53 (6.01)	1.67 (4.69)	-2.304 (.02)	-0.228
	Risky drinking daysd	207	1.25 (3.78)	0.70 (2.58)	-2.008 (.4)	-0.199
	Illicit drug-use days	206	3.22 (7.57)	2.14 (6.55)	-2.499 (.01)	-0.248
QoLe
	Overall QoL	202	28.47 (6.46)	30.03 (7.11)	3.653 (<.001)	0.370
	Physical subscale QoL	206	13.20 (3.01)	13.48 (3.11)	1.682 (.09)	0.167
	Mental subscale QoL	204	9.75 (2.99)	10.77 (3.50)	3.892 (<.001)	0.393
Health care utilization in last 6 months
	No. of hospitalizationsd	207	0.43 (1.03)	0.22 (0.65)	-3.357 (.001)	-0.335
	No. of ERf visitsd	207	1.10 (2.79)	0.75 (1.31)	-1.911 (.06)	-0.189

^aZ, provided in the Wilcoxon sign test, is the standard normal distributed Z-value used to test the significance between outcomes reported at two time points (eg, pretest vs 6 months).

^bFor Z and d values, negatives mean decreases and positives mean increases in values from baseline to 6 months.

^cCalculated from effect size d. On the basis of Cohen (1988) effect size, small: d=0.2, medium: d=0.5, large: d=0.8.

^dRisky drinking days, hospitalizations, and ER visits: Those who reported no such events were coded with zero in the number of days of these events.

^eQoL: quality of life.

^fER: emergency room.