Background: Family physicians are central care providers for older adults. Some family physicians have enhanced skills to care for this patient population, sometimes reflected in a focused medical practice and/or extra training. There are knowledge gaps concerning how to identify physicians with focused practice or added training within health administrative data, as well as understanding their contributions to quality primary care. Research Question: This thesis investigated: (1) What are appropriate and important performance measures of family physician services that are relevant to older adults? (2) How can family physicians with focused practice or added training be classified within population-based health administrative data, and what are their medical practice characteristics? (3) How do family physicians with/without focused practice or added competence compare in delivering high quality care to older patients? Methods: This thesis comprised a modified Delphi consensus study and two population-based observational studies. Expert panelists rated indicators and refined proposed technical definitions for endorsed indicators. Using health administrative data, family physicians with focused medical practices and/or added competence were classified, and their practice- and provider-level characteristics were described. A propensity score-matched cohort study enabled comparisons of family physicians on the consensus-based performance measures. Results: This thesis established consensus on 12 measurable processes across four priority topics relevant to added competency training. An approach to classify family physicians with focused practice or added training was developed, and practice differences were identified. Lastly, this work operationalized the technical definitions of performance measures and identified distinctions on four processes. Conclusion: This thesis provides novel data on the family physician workforce with focused medical practices and added competence to care for older adults. The studies demonstrated the feasibility of establishing measurable indicators using a modified Delphi procedure, and developed an approach to classify focused practice physicians and added competency holders within health administrative data. / Dissertation / Doctor of Philosophy (PhD) / Older adults frequently seek care from family doctors for a variety of health needs. Some family doctors focus their medical practice to increasingly care for older patients or undergo extra training to learn more about their needs. There is a research gap in understanding if added focus or training impacts the care that older adults receive. This thesis studied family doctors with focused medical practices and extra training to see how they compare with other family doctors. Experienced physicians and researchers were consulted to determine what primary care activities related to caring for older patients are most important and appropriate to measure. Findings showed some practice differences between family doctors who focus on older patients or have extra training, but the quality of care that older adults receive is similar. This research suggests that added focus and training might not lead to better quality of primary care for older patients.