A multiple outcall approach based on the Transtheoretical Model was used to encourage mammography behavior in low-income women in the state of Colorado. Women (n = 983) were recruited in person at grocery and discount stores and were then called over the telephone to receive the multiple outcall intervention. These women were compared with 3,080 women who were recruited by telephone and randomly assigned to three study groups: health survey only (control); single outcall; or advance card +

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... e outcall. Subsequent mammography behavior was assessed through a telephone interview conducted 6 months after initiation of the protocol. After controlling for baseline differences between groups in age, education, income, health status, and previous mammography behavior, the multiple outcall intervention was significantly related to mammography behavior among women nonadherent at baseline (odds ratio, 2.58; 95% confidence interval, 1.45-4.60). Furthermore, women who received the multiple outcall intervention had higher "stage of change" at follow-up and more positive attitudes toward mammography. Cost-effectiveness analysis indicated that although the multiple outcall intervention was more costly to deliver ($14.84 per subject compared with about $7.00 for the single outcall interventions), it cost considerably less per subject converted from nonadherent to adherent. Despite study design limitations, the multiple outcall intervention appears to be an effective method of promoting mammography among previously nonadherent women. The results suggest that a combined approach, in which nonadherent women receive multiple calls promoting screening behavior, followed by single calls at the appropriate intervals to promote repeat screening, may be a useful strategy in defined populations.