The evaluation step in a public relations program is essential. It permits the practitioner to assess the effectiveness of the effort, demonstrate that effectiveness to management, and plan for future efforts. It also gives an opportunity to adjust tactics while the campaign is in progress. All this means that competent evaluation demonstrates the value of public relations to management.

Evaluation techniques may include impact analysis, audience coverage, audience response, campaign impact, and environmental assessment.

Value is more important than volume in evaluating the effectiveness of public relations efforts. The number of news releases sent to media and even the number used by the media does not equal value in public relations. Traditionally, public relations practitioners have measured output in terms of what was sent and used by media. But this approach doesn't assess quality, cost-effectiveness, or opportunity for improvement. Instead, the evaluation should be measuring changes in behavior, attitudes, knowledge, or awareness.

Public relations effectiveness is best measured using an open-system model that takes into account environmental factors and before-and-after comparisons. Open-system evaluation models include effectiveness measures of administrative processes, employee publications, media relations, and advertising.

"Evaluation combines research findings with judgment, past experience, and values to determine the worth of public relations efforts."
     —Glen Broom, Professor
       San Diego State University