Cross-sectional study

Cross-sectional studies form a class of research methods that involve observation of some subset of a population of items all at the same time as distinct from longitudinal studies that are conducted over time. A cross-sectional study is a descriptive study in which several variables, e.g. disease and exposure status, are measured simultaneously in a given population. Cross-sectional studies can be thought of as providing a "snapshot" of the frequency and characteristics of a disease in a population at a particular point in time. This type of data can be used to assess the prevalence of acute or chronic conditions in a population. However, since exposure and disease status are measured at the same point in time, it may not always be possible to distinguish whether the exposure preceded or followed the disease.