Four left columns: Percentage of random prompts at which participants reported smoking tobacco, by degree of reported cocaine craving. Two right columns: Percentage of event-contingent prompts at which participants reported smoking tobacco. The denominators for the six bars were: 12,569 (cocaine craving rated 0); 8,125 (cocaine craving rated 1); 2,373 (cocaine craving rated 2); 1,792 (cocaine craving rated 3); 597 (event-contingent cocaine-craving entry); 665 (event-contingent cocaine-use entry). The bars show raw percentages, whereas the statistical results are adjusted for sex, race, age, and location. The pattern of covariate-adjusted percentages (not shown) was similar to the pattern of raw percentages.