Justifying age thresholds for mammographic screening: an application of pragma-dialectical argumentation theory.

Information campaigns on breast cancer screening in the Netherlands need to convince women above 50 years of age to have biannual mammography, and women below 50 years of age that regular mammograms are not recommended for them. This article reports the results of two experiments in which the construction of the persuasive messages was informed by argumentation-theoretical insights. No differences were found between either statistical and anecdotal evidence or gain- and loss-framing in the attempt to convince women under 50 that they normally do not need regular mammography. A striking contrast emerged, however, between the overwhelming acceptance of breast cancer screening for women above 50 and the relative restraint and reluctance to consent that mammography is usually not recommended for women under 50. The reluctance to accept that regular mammography is not recommended for women under 50 is traced back to ego involvement.