Richard Skolnik, lecturing in Yale's Essentials of Global Health course, explains how researchers measure the global burden of disease. He walks through the DALY, a metric combining years lost to premature death with years lived with disability, and shows how it lets health planners compare wildly different conditions on the same scale. The session covers key demographic factors, including fertility, mortality, and population age structure, and how these shape a country's health profile. Skolnik then works through the leading causes of illness, disability, and death worldwide, tying each to specific risk factors such as malnutrition, unsafe water, and tobacco use. The lecture is built for students with no prior public health background, using plain language and concrete examples rather than technical jargon, and sets up the course's later sessions on specific diseases and interventions.