The objective of this course is to teach basic architecture of clinical and health services research with an emphasis on three critical components: the population, interventions and outcomes. Students also learn about different study designs, specific challenges in both observational and interventional studies, and methods of addressing potential biases. Basic principles of measurement for categorical and continuous data, including the sources of variance for such data are emphasized. Students learn how to evaluate validity and reliability of data and critical appraisal of the published literature to illustrate threats to validity. By the end of the course, students are able to read the literature critically and develop detailed proposals for their own projects.