Ninety percent of the Los Angeles subjects and 60% of the Helsinki subjects answered “yes” to the question, “Have you ever seen an advertisement for cigarettes”? (chi square = 107.7, p <.001). However, seventy percent of the Los Angeles subjects compared with only 29% of the Helsinki subjects reported that they had seen a cigarette ad within the past week (chi square = 167.2, p < .001). The modal length of time since seeing a cigarette ad fell into the category of “one to three years ago” for Helsinki subjects and into the category of “not today, but less than a week ago” for Los Angeles subjects. Twice as many Los Angeles subjects (80%) as Helsinki subjects (40%) reported that they had seen a cigarette ad in a magazine (chi square = 129.4, p <.001).
Eleven variables involving media use and advertising were factor analyzed. Three items (ever seen cigarette ad, recency of seeing cigarette ad and saw cigarette ad in magazine) were found to form a factor: This three-item factor was used as our measure of cigarette advertising exposure. The factor structure was identical for the two samples, but the factor variances were significantly different. Pearson correlation coefficients among the three variables for the Helsinki sample were: ever seen ad with recency, r = .694 and with ad in magazine, r = .470, and recency with ad in magazine, r = .496. For the Los Angeles sample Pearson correlation coefficients were: ever seen ad with recency, r = .412 and with ad in magazine, r = .223, and recency with ad in magazine, r = .240.
Significantly more Los Angeles subjects (65%) than Helsinki subjects (50%) answered that at least 60 out of every 100 adults “smoke cigarettes most days” (chi-square = 35.3, p < .001). The extent of overestimation was markedly greater for Los Angeles subjects than for Helsinki subjects: Since actual adult smoking prevalence in Los Angeles was only 21% at the time of the study, “60 out of every 100” represents a 186% overestimate. The same response represents only a 46% overestimate for Helsinki subjects, since actual adult smoking prevalence in Helsinki was 41%. Subjects in both countries were less likely to overestimate smoking by peers, although the same relationship of prevalence estimates to city of residence was obtained, with Los Angeles subjects being more likely than Helsinki subjects to overestimate. In response to the question, “Out of every 100 students your age, how many do you think smoke cigarettes at least once a week?”, 30% of the Los Angeles subjects and 18% of the Helsinki subjects answered 30% or more (chi-square = 25.7, p < .001). As was the case with adults, actual smoking prevalence is also much greater for Helsinki adolescents than for Los Angeles adolescents: 20% of Helsinki junior high school students compared with only 8% of Los Angeles junior high school students reported smoking during the past 24 hours.. A zero-order correlation of .293 (p < .0001) between estimates of adult smoking prevalence and estimates of peer smoking prevalence was obtained for the Finnish sample, and a correlation of .390 (p < .0001) was obtained for the United States sample.
There were no significant differences in intention to smoke, with 70% of the Helsinki subjects and 71% of the Los Angeles subjects answering “no” to the question, “Do you think you will ever smoke cigarettes in the future?”.
Traditional multiple-regression path analysis was used in two models, for samples from Finland and the United States, respectively. For each model, three simultaneous multiple regressions were conducted with (1) intention to smoke regressed on two measures of estimates of smoking prevalence; (2) estimates of smoking prevalence regressed on the cigarette advertising exposure factor, and (3) intention to smoke regressed on cigarette advertising exposure. Results for the two models, with t values, are shown in and .
Multiple regression with t values of intention to smoke, perception of adult and peer smoking prevalence, and cigarette advertising exposure for Los Angeles subjects (* p < .05; ** p < .01; ***p < .001).
Multiple regression with t values of intention to smoke, perception of adult and peer smoking prevalence, and cigarette advertising exposure for Helsinki subjects (** p < .01; *** p < .001).
As seen in , among the Los Angeles subjects, significant relationships exist between advertising exposure and perceptions of both adult smoking prevalence (t=3.582, p <.001) and peer smoking prevalence (t=2.964, p <.01). Perceived peer smoking prevalence was, in turn, significantly related to intention to smoke for the Los Angeles subjects (t=2.348, p <.05). Thus, in the Los Angeles sample, there was evidence for significant mediation by the joint significance test (MacKinnon, Lockwood, Hoffman, West, & Sheets, 2002
). For the Helsinki subjects, as shown in , only the relationship between advertising exposure and perceived peer smoking prevalence was significant (t=2.926, p <.01). However, in the Helsinki sample, neither perceived peer nor adult smoking prevalence was significantly related to intention to smoke; thus, in this sample, by the joint significance test, there was no evidence for mediation. Finally, a significant, residual direct effect of cigarette advertising exposure on intention to smoke (after taking the mediators into account) was not found for either group of subjects.