Table 3.

Logistic Regression Analyses of Rating Scale Scores, Specific Binding Volume of Distribution, and the Combined Model of Rating Scale Scores Plus Specific Binding Volume of Distribution for the Prediction of Quit Status With Treatment^a

Variable	Rating Scale Score		VS/fP		Rating Scale Score + VS/fP
	χ2 (df)	P Value	χ2 (df)	P Value	χ2 (df)	P Value
Wald χ2
FTND score	0.1 (1)	.77			0.002 (1)	.96
UTS craving scale score	4.9 (1)	.03			2.6 (1)	.11
Self-efficacy	1.6 (1)	.21			0.4 (1)	.51
VS/fP			17.1 (1)	<.001	10.5 (1)	.001
Model χ2	11.0 (3)	.01	26.4 (1)	<.001	30.7 (4)	<.001

Abbreviations: FTND, Fagerström Test for Nicotine Dependence; UTS, Urge to Smoke; V_S/f_P, specific binding volume of distribution.

^aLogistic regression analyses of quit status as determined by rating scale scores alone, V_S/f_P values alone, and all measures combined. Comparison likelihood ratio χ² test results were as follows: for rating scale score + V_S/f_P vs rating scale score, ${\mathrm{\chi }}_1^2=19.8$, P < .001; for rating scale score + V_S/f_P vs V_S/f_P, ${\mathrm{\chi }}_3^2=4.3$, P = .23. Likelihood ratio tests show that V_S/f_P significantly increases the predictive power of rating scale scores but that rating scale scores do not significantly supplement the predictive power of V_S/f_P values.