The purpose of this study was to determine how people weigh both median survival time and 1-year survival probability when considering a choice between palliative Cisplatin-based chemotherapy with best supportive care (C+BSC) versus best supportive care alone (BSC) as treatment for advanced non-small cell lung cancer (NSCLC). Sixty people, previously treated for cancer, were interviewed as surrogate patients making a treatment decision. The interview included a structured description of the treatment options, and trade-off exercises used to clarify the participants' attitudes pertaining to the survival probabilities associated with each treatment.Participants' attitudes ranged from choosing the more toxic treatment if it offered no survival advantage to declining C+BSC no matter how large its advantage. Fifty-seven percent of participants would choose chemotherapy if the 1-year survival were 10% higher with C+BSC than with BSC alone. For 44 participants (76%), both their median survival and 1-year survival thresholds for accepting C+BSC were consistent, and for two (3%), neither threshold was consistent with their stated treatment preference. For the remaining 12 (21%), one threshold was discordant, but in all cases, this threshold was less relevant to his/her decision. Participants' thresholds could not be predicted reliably on the basis of patient age, sex, education, preferred role in treatment decision making, or previous treatment with chemotherapy. All but one participant recommended the interview as a decision-support strategy for actual patients. The findings suggest that patients with advanced NSCLC should be offered more than one treatment option, and that a systematic process for educating patients and for eliciting their preferences is desirable. The process described herein has potential for use in this clinical setting.