What is shared in shared decision making? Complex decisions when the evidence is unclear.

Patient involvement in decisions is central to patient-centered care. Yet many important decisions must be made in complex, ambiguous clinical situations in which all possible options cannot be known, evidence is inadequate to inform patients' preferences fully, and/or patients are unclear about their desired level of involvement. In these situations, preferences are shaped by affect, framing, and "collaborative cognition" among clinicians, patients, and their families; thus, decisions are often relational, dynamic, iterative, provisional, and/or conditional. Clinicians can help patients achieve greater autonomy by engaging both intuitive and deliberative decision-making processes ("whole mind") and involving others in exploring, clarifying, and co-constructing patients' preferences ("shared mind"). Clinical and interpersonal relationships can promote effective decision making through developing a shared attentional focus, tailoring information, and identifying conditions under which provisional preferences might change. Information technology and health systems offer untapped potential to deepen the relationships and conversations within which decisions are made.