Formal study of a public health intervention that usually focuses on the intermediate objectives in the continuum of process, impact, and outcome. Impact measures are usually short term and process oriented, such as immunization coverage rates linked to an intervention like a vaccination program, and that logically precede long-term outcomes, such as reduced incidence rates of vaccine-preventable disease. The term is also applied to assessment of effects that can be expected, or that have occurred, as a result of significant changes in an environment or habitat but usually is applied to midcourse and short-term evaluations and may focus on whether objectives have been or are being achieved. Impact assessment is preferably outcome oriented, rather than process oriented, but meaningful outcome measures are not always feasible or available.
Subjects: Public Health and Epidemiology.