Population screening

This chapter outlines the concept and definition of population screening. It identifies key challenges and considerations in converting the simple concept of early identification of disease into population screening programmes. Ethical considerations are important in evaluating the potential benefits and harms of screening programmes. These inform the criteria used to determine whether it is appropriate to introduce screening. Screening tests must usually be sensitive to maintain public confidence in a screening programme, but specific tests are also required because false positives may often outnumber true positives in a population screening context. Assessment of screening programme effectiveness usually requires randomized controlled trials that minimize the potential effects of lead time and length bias. The chapter concludes by discussing policy decisions involving starting, stopping, and changing programmes, as well as how screening programme performance can be measured.