Understanding health decision making: An exploration of homophily.

The phenomenon of homophily first was described in Lazarsfeld and Merton's classic 1954 friendship analysis as a tendency for friendships to form between those who are alike in some respect. Although theories of decision making address a host of factors that affect the process, the influence of individuals with homophilic ties remains unaccounted for and unexplained. The purpose of this paper is to review theories relevant to decision making and describe what is known about the relationship between homophily and health care decision making. Further, we provide new evidence suggesting the influence of homophily on decision making in results from a randomized, multi-center clinical trial of American men with localized prostate cancer. A diverse sample of 293 men with a new diagnosis of localized prostate cancer reported relevant personal factors influencing the care management decision before randomization to a decision aid or usual care, between 2013 and 2015. Among these personal factors were the level of influence or importance ascribed to various individuals at the time of the treatment decision. One month later, participants reported how prepared they were for decision making. 123 men (42%) reported friends and/or coworkers as information sources, of which 65 (53%) indicated that friends and/or coworkers influenced the care decision. Men who reported friends/coworkers as information sources had significantly higher one-month preparation scores. Our review of decision making theories and practical applicability suggests the influence of homophilic relationships manifests in health care decision making. Faced with a list of options to manage health conditions, decision makers turn to known individuals in their environments, particularly those individuals with whom the decision maker can identify. Clinicians may solicit information from patients about influential others and explain how that support fits into the health decision at hand without dishonoring the importance of the homophilic relationship.