Observational Research Designs

Abstract

AbstractObservational studies do not dictate the cancer screening regimens that their study subjects utilize. Instead, these studies collect data on individuals’ cancer screening practices, cancer outcomes, and other factors if needed. Because no regimens are dictated, an observational study can capture information about and evaluate a variety of cancer screening practices, including use of different tests or cancer screening regimens. Observational studies can be retrospective or prospective in nature, with the distinction dependent on how and when individuals are chosen for study inclusion. Observational studies provide weaker evidence than experimental studies because observational studies are subject to confounding. Confounding occurs when a third factor is associated with both the cancer screening practice and cause-specific mortality, meaning that the third factor is not equally present among groups of individuals with different cancer screening practices and is not equally present among groups of individuals with different cancer outcomes.