Effectiveness of Warnings

The purpose of the present work was to identify some of the factors that influence effectiveness of warnings. Two laboratory experiments designed to examine behavioral effectiveness indicated that a warning placed before procedural instructions is more likely to lead to compliance than a warning that follows instructions. Two rating experiments indicated that for greatest perceived effectiveness, environmental warnings generally require a signal word plus hazard, consequence, and instruction statements. A third rating experiment suggested that informative, nonredundant statements add to a warning's perceived effectiveness. Several field demonstration studies showed that cost of compliance and salience influence behavioral effectiveness. Implications and applications to warning design are discussed.