When the craving, positive, and negative mood scales were evaluated for reliability using Cronbach’s alpha, for each assessment time, the alphas ranged from .77 to .95 for craving, .86 to .88 for positive mood, and .86 to .91 for negative mood. A correlational analysis was conducted with positive and negative mood scores. Mean positive mood scores for each participant (N=72), taken at each assessment point (before, after, and random), were highly correlated with each other (range .94 to .89). Likewise, negative mood scores were also highly correlated with each other (.94 to .91). However, positive and negative mood scores were only modestly negatively correlated (range −.44 to −.55). This indicates that positive and negative self report are not simply mirror images of each other and should be treated as separate scales (Watson, Clark, & Tellegen, 1988).
