Background: Patient engagement has become a priority for healthcare organizations, yet remains inconsistently defined. Patient engagement has also become a priority for healthcare providers. Current discourse suggests that patients today desire more control over medical decision making than ever before, and that the proliferation of online health information is empowering patients to make autonomous medical decisions. Yet, prior research indicates that patients typically prefer to share decisions with their physician, raising questions about what patient engagement is and whether preferences have changed over time. Methods: This study addresses multiple research questions using three phases of data collection. Phase one asked: how are ‘patient engagement’ and ‘patient advocacy’ defined and perceived by individuals who are involved in engagement and advocacy activities? This question was addressed by conducting semi-structured key informant interviews (N=11). Phases two and three examined preferred roles in medical decision making among cystic fibrosis (CF) patients, caregivers, family members and patient advocates, and whether these roles were related to: trust in the physician, self-assessed health information literacy and demographics. Phase two involved conducting a quantitative cross-sectional survey (N=165), which included three scales: the Problem-Solving Decision-Making Scale (PSDM), the Trust in Physician Scale (TPS), and the electronic Health Information Literacy Scale (eHEALS). T-tests and logistic regressions were computed to determine the relationships between variables. Phase three involved interviewing a subgroup of survey participants to help to explain survey results (N=19). Thematic analysis was used to identify common themes. Results: Our findings suggest that patient engagement and advocacy have multiple meanings, that most survey participants preferred to share medical decisions with their physician (>80%), and that self-assessed health information literacy was associated with preferred roles; as eHealth literacy went down, so did desire for participation in making medical decisions. Follow-up interviews supported these results; participants mentioned how they assessed the credibility of online health information and how they preferred to direct questions to their physician. Conclusion: This research highlights the need for clear language regarding patient engagement activities. This study also suggests that eHealth literacy may influence decision making preferences, and that preference for autonomous decision making should not be assumed.