Factors influencing the effectiveness of warnings

Warnings are one of several hazard control methods that can be used to protect people and property against dangers and loss. This article surveys the factors known to influence the effectiveness of warnings. The presentation of this material is organized around a sequence of stages of a human information processing model that begins with the presence of warning information leading to attention, comprehension, beliefs/attitudes, motivation and ends with compliance behavior. Whether a warning is noticed and attended to often depends on whether it is conspicuous relative to other stimuli in the environment. Research showing ways to make warnings conspicuous are described. Given that a warning is noticed and attended to, the message must also be understood in order for the warning to be effective. The message must be tested with a representative sample of the target population in order to ensure comprehension. However, even if the warning is understood, it still might not lead to compliance behavior if the message does not fit with people's existing attitudes and beliefs and is not sufficiently persuasive to change those attitudes and beliefs. Finally, the warning also needs to energize or motivate people to comply with the warning and this will depend on such factors as cost (e.g., time, effort, money) of performing the requested compliance behavior as well as the costs imposed on noncompliance. lmplicati.ons for practical application and gaps in current knowledge are discussed.