Descriptive studies

Abstract

Descriptive studies are observational studies which range from the case and case series report to extensive epidemiological studies. The essential features of the descriptive studies are its cross-sectional nature. From an epidemiological perspective, there are two types of descriptive studies; prevalence studies and ecological studies. In prevalence studies, the focus is on describing disease and exposure variables with reference to person, place and time on an individual level. They help to assess the disease and sometimes the exposure burden. Sequentially conducted descriptive studies can give time trends. Case-control analysis of descriptive studies can help identify an association, which could be tested by true analytical studies like case-control and cohort studies. The essential validity threats to descriptive studies are selection bias and information bias. Using appropriate random sampling methods, taking steps to prevent response failure and administering validated questionnaires for data collection are the measures to circumvent them. Cross-sectional designs are also used to validate diagnostic tests and research instruments, staging of illnesses and deriving normative values.