Family discordance about treatment decisions can greatly compromise the quality of life of cancer patients and family caregivers. Family members often urge advanced cancer patients to accept futile care that can impair their quality of life. Disputes over treatment decisions further undermine caregivers' physical and psychosocial well being. This study will develop a new measure that can validly and reliably assess the likelihood and degree of family discordance about cancer treatment decisions. The new measure will be used by physicians to obtain a clinical assessment and researchers to conduct scientific studies. The creation of this new measure will fill an existing gap in clinical and health services research. During the first study year, a series of focus groups will be conducted among 120 advanced lung cancer patients, family caregivers, and health care providers to identify all aspects of family discordance about treatment decisions. We will develop a Family Concordance Scale that will contain an initial pool of scale items and a Family Concordance Semi-Structured Questionnaire to collect information about family discordance in real life settings. In the first half of Year 2, the pool of scale items will be piloted among 50 family units, consisting of 50 advanced lung cancer patients, as well as 50 primary and 50 secondary family caregivers. Revisions will be made accordingly. In a two-year period, research assistants will conduct two interviews apiece with 250 family units (750 subjects). In addition, several psychometric instruments that measure presumptive correlates of family discordance will be administered at baseline (T1). Following the second interview, a measure that assesses physicians' estimates of family discordance about treatment decisions will be completed by oncologists. Chart review will also be conducted to collect patients' medical and demographic information. The last six months of the study will be devoted to examining the psychometric and statistical properties of the scale, especially its validity and reliability. The final product of this study will be a valid and reliable scale that can be administered within 10 minutes. Cut-off scores will be provided for classifying concordant and discordant families. In addition, rich and detailed descriptive information about the family treatment decision-making process will be provided.