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.

Three experiments are presented examining the effects of warning layout (spatial structure) and organization (semantic structure) on the readability and memorability of warning information. In Experiment 1 these factors were tested in a 2 (levels of layout) x 3 (levels of organization) factorial design. The two levels of layout were the typical paragraph format and an experimental version having the appearance of an outline. Warning content was organized according to hazard, type of statement, or randomly. Warnings were ranked according to three criteria; eye appeal, ease of processing, and effectiveness. In general, warnings in outline layout and type of hazard organization were ranked as having greater eye appeal, easier to process, and more effective than alternative organization-layout conditions. In Experiments 2 and 3, only warning layout was manipulated and a cover story was used to elicit reading and compliance behaviors likely to occur in the home. Experiment 2 results indicate that, when asked to read the warnings, subjects spent less time reading warnings in paragraph layout than warnings in oultine layout. In Experiment 3, the decision to read the warning was at the discretion of the subjects. Results indicated that warnings in outline layout were read and complied with by a larger proportion of subjects than warnings in paragraph layout. Implications for warning design and future research are discussed.

This research examines several characteristics of consumer products that influence warning communication. Seventy-two generically-named products were rated according to perceived hazardousness, familiarity, and several other measures: 1) willingness to read warnings, 2) need for warnings, 3) location of warnings, and 4) appearance of products with warnings. The results indicate that reported willingness to read warnings is strongly and positively related to the perceived hazardousness of the product. Though product familiarity is significantly related to willingness to read warnings, it provides little predictive value beyond hazardousness. Additional analyses showed, the more hazardous the product: 1) the greater the need for warnings, 2) the closer to the product one expects to find a warning, and 3) the less warnings detract from the appearance of such products. Implications of these results are discussed with regard to applications for warning design.

Two questionnaire studies were conducted examining potential components of perceptions of consumer product hazardousness. In Study 1 subjects rated 72 consumer products on perceived hazardousness, expected seventy of injuries, and perceived likelihood of injury. The results indicate that seventy relates more strongly than injury likelihood with perceived hazardousness. Several product knowledge variables were also examined; these results indicate that technological complexity and confidence in knowing the product's hazards add unique variance beyond severity in the prediction of hazard perception. In Study 2 subjects generated accident scenarios for each of 18 consumer products. Subjects rated each scenario according to the severity of the accident and the probability of its occurrence and also provided ratings of overall product hazardousness. Results supported the findings of Study 1. The severity of product injury scenarios were strongly and positively correlated with hazardousness. Probability of injury ratings added negligible hazard predictiveness beyond severity. Product hazardousness was highly correlated with the level of precaution subjects would reportedly take when using the product. For high hazard products the first scenario generated was most severe compared to the other two scenarios. For low hazard products, the fist scenario was most probable and the least severe of the scenarios generated. Practical and theoretical implications of the results are discussed.

Traditionally, integrated system validation (ISV) testing for proposed nuclear power plant control room design changes has been completed prior to the U.S. Nuclear Regulatory Commission (NRC) approving the proposed change. This, however, can pose scheduling challenges for proposed changes to operating facilities. The NRC is therefore considering possible alternatives for licensees to provide the human factors engineering validation information necessary to demonstrate reasonable assurance of safety for proposed design changes. One such alternative could be the use of early-stage testing results from a multi-stage validation (MSV) program. If early-stage results, along with other design considerations, can provide sufficient supporting information, the NRC may be able to make a safety determination for a proposed design change prior to the completion of ISV testing. Licensees proposing such an approach should consider available industry standards discussing MSV, in conjunction with existing NRC guidance where applicable, when developing their validation program and establishing success criteria. The NRC intends to engage in future discussions with stakeholders regarding the potential development of additional NRC-endorsed guidance on the use of MSV to support proposed changes to existing facilities, as well as designs for new reactor control facilities.