In strategic communication management, the most meaningful indicator of success—especially for a safety communication project—is a measurable change in behavior. Option D is correct because the ultimate purpose of safety communication is not merely to inform or persuade, but to reduce risk by changing how people act in real situations.

Awareness, knowledge, and attitudes are all important intermediate outcomes, but they do not guarantee safer workplaces on their own. Employees may be aware of safety rules, understand procedures, and even express positive attitudes toward safety, yet still fail to follow protocols under time pressure, habit, or cultural norms. Strategic communication management emphasizes that outcomes should be evaluated at the level that most directly supports the organizational objective—in this case, preventing injuries and incidents.

Behavior change provides tangible evidence that communication has translated into action. Examples include increased use of protective equipment, consistent adherence to safety procedures, reporting of hazards, or reductions in unsafe practices. These indicators directly correlate with improved safety performance and can often be validated through incident data, audits, or observational assessments.

The other options represent earlier stages in the communication impact hierarchy. Awareness answers whether messages were noticed. Knowledge measures whether information was understood. Attitudes reflect beliefs or perceptions about safety. While these measures help diagnose progress and inform improvements, they are insufficient as final indicators of success for a safety initiative.

Strategic communication management stresses outcome-based evaluation. Communication is considered effective when it supports organizational goals through observable results. In safety contexts, that result is safer behavior. Measuring behavior change demonstrates accountability, validates investment in communication efforts, and confirms that communication has achieved its intended purpose—protecting people and reducing risk—making it the strongest indicator of success.