Building upon existing evidence to shape future research endeavors.

PURPOSE The identification, retrieval, and critical evaluation of biomedical literature to inform the development of future research efforts are discussed. SUMMARY A literature search should be designed with the consideration of the desired scope of the information, discipline, or therapeutic area; the nature of the publication or presentation; the ease of full-text documents; and the frequency of updates. Published literature, as well as research abstracts and clinical trial registries, are good sources of information for investigators. Building upon the past efforts of others may give insight into study design techniques that are of particular value, areas in which the literature is lacking, and potential research pitfalls that should be avoided. Early research efforts are often susceptible to methodological flaws, small sample sizes, or poor reporting approaches. Reviewing the research literature can uncover these and other suboptimal study approaches. Variables that can influence study results, such as sex, age, health status, concomitant diseases and medications, medical history, economic status, and disease severity, should be anticipated and minimized. The acronym PICO (patients, intervention, comparison, and outcomes) is commonly used to describe the integral steps of constructing a study. Alterations that may need to be made to improve the study may include broadening inclusion criteria, prolonging the length of the enrollment period, increasing sample size or number of study centers, and lengthening the follow-up period. CONCLUSION A thorough review and analysis of the literature can aid one in avoiding duplication of completed or current research projects. A survey of the research landscape can also ensure the novelty of the research question, as well as determine methods that may be adapted to meet the study design needs.