Figure 1.

Sensitivity to detect smoking and specificity for verifying abstinence in the prior 24hr are shown by carbon monoxide (CO) cutoff values (i.e., minimum criterion to designate smoking), separately (top) and as total accurate detection (i.e., the percentage of true detections of smoking and abstinence; bottom). Plots are presented for smokers who are high (n = 103) versus low (n = 158) in quit interest and for those reinforced (n = 127) versus not reinforced (n = 134) for abstinence.