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Types of Evaluation

Historical Document

This document is provided by the Agency for Toxic Substances and Disease Registry (ATSDR) ONLY as an historical reference for the public health community. It is no longer being maintained and the data it contains may no longer be current and/or accurate.

(NCI 1992)

The following types of evaluation have been adapted to serve the goals of evaluating risk communication programs.


Evaluation during the formative stages of a risk communication effort assesses the strengths and weaknesses of materials or campaign strategies before implementation. It permits necessary revisions before the full effort goes forward. Among other things, materials can be tested for the following characteristics:

  • clarity
  • tone
  • comprehensiveness
  • anticipated reactions.


Process evaluation examines the procedures and tasks involved in implementing an activity. This type of evaluation also can collect the following information about the administrative and organizational aspects of the overall effort:

  • number of staff working on the project
  • schedule of activities
  • number of materials distributed
  • attendance at meetings
  • number of calls to a hotline
  • number of public inquiries received as a result of a public service
  • announcement
  • articles printed.


Outcome evaluation is used to collect and present information needed for judgements about the effort and its effectiveness in achieving its objectives. Not all risk communication efforts are suitable for outcome evaluation. Outcome evaluation is most suitable when the program has clear and measurable goals and consistent replicable materials, organization, and activities. Outcome evaluation can obtain descriptive data on a project and document the immediate effects of the project on the target audience (e.g., percent of the target audience showing increased awareness of the subject).

An outcome evaluation can collect the following information about the program:

  • changes in knowledge and attitudes
  • expressed intentions of the target audience
  • changes in behavior.


Impact evaluation focuses on the long-range results of the program and changes or improvements in health status as a result. It is designed to identify whether and to what extent a program contributed to accomplishing its stated goals (more global than outcome evaluation). In a "real world" environment, there are many factors that influence an individual's health behavior, including peer support and approval, self-esteem and other individual characteristics, advertising and mass media coverage of health, and community and institutional factors (such as availability of services).

It is usually extremely difficult to separate the impact of a health risk communication program from the effects of other confounding variables on an individual's behavior. Thus, the results of an impact evaluation often cannot be directly related to the effects of an activity or program because of the other (external) influences on the target audience which occur over time. Impact evaluations are rarely possible because they are frequently costly, involve extended commitment, and may depend upon other strategies in addition to communication. Information obtained from an impact study may include the following:

  • changes in morbidity and mortality
  • changes in absenteeism from work
  • long-term maintenance of desired behavior
  • rates of recidivism.

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