This study adds to the literature in several relevant ways. First, it is the first study to evaluate, at the population level, whether the elevated risk of adverse health outcomes associated with sleep duration is explained by perceived insufficient sleep. Put simply, this study explores the role of perceived unmet sleep need in the relationship between sleep duration and health. Although insufficient sleep was associated with adverse outcomes, our data show that the variance explained is not greater than or separate from that explained by sleep duration, in most cases. Second, this study documents a population-level association between sleep duration/insufficiency and cardiometabolic disease, using a population-weighted dataset, adjusting for a very wide array of potential confounders. The cardiometabolic endpoints investigated represent some of the leading causes of death (e.g., myocardial infarction and stroke), or major risk factors for those events (e.g., obesity, hypertension, hypercholesterolemia). Third, this study documents that among habitual short sleepers, two sub-groups emerge: the “short” sleepers who are more populous, and the rarer “very short” sleepers, who report