Smokers' unrealistic optimism about their risk.

OBJECTIVE: Past studies have produced ambiguous or inconsistent results when testing whether smokers actually underestimate their own risks of experiencing tobacco related illness. Whereas smokers claim that they are less at risk than the average smoker on self administered questionnaires, this unrealistic optimism has not been found in telephone or face-to-face interviews. We avoided the measurement problems of past studies and examined responses to a number of new questions to assess different aspects of smokers' perceptions. METHODOLOGY: A US national telephone survey (n = 6369; 1245 current smokers) posed a variety of questions designed to examine beliefs about the risks of smoking. For key questions, separate samples of smokers were asked either about their own risk or about the risk of the average smoker. RESULTS: Smokers underestimated their relative risk compared to non-smokers and, contrary to previous interview surveys, believed they have a lower risk of developing lung cancer than the average smoker. Furthermore, their perceived risk of lung cancer and of cancer in general barely increases with the number of cigarettes smoked per day, and their estimates of their risk of cancer are actually slightly lower than their estimates of their risk of lung cancer. Substantial proportions of smokers and former smokers agree with several myths, more than half agreeing that exercise undoes most smoking effects. CONCLUSION: Smokers underestimate their risk of lung cancer both relative to other smokers and to non-smokers and demonstrate other misunderstandings of smoking risks. Smoking cannot be interpreted as a choice made in the presence of full information about the potential harm.

Perceived probability, perceived severity, and health-protective behavior.

It seems obvious that 2 key attributes of health hazards, their perceived probability and perceived severity, do not act independently on the motivation to engage in protective behavior. If a health problem is perceived to have no chance of occurring, there should be no interest in acting against it, regardless of how serious it might be. Nevertheless, researchers seldom observe the expected interaction between probability and severity. A case study approach was used to examine how probability and severity combine to influence interest in protection. Ratings of motivation to act, probability, and severity for 201 hazards were collected from 12 participants, and data were analyzed for each person separately. Analyses revealed the expected Probability x Severity interaction. Additional calculations showed why it is difficult to detect this interaction using between-subjects designs. The data also revealed that people are surprisingly insensitive to variations in hazard probability when probabilities are in the moderate to high range.

What does it mean to understand a risk? Evaluating risk comprehension.

Risk communications are frequently intended to help people understand hazards they face, with the hope that this understanding will help them make better decisions about the need for action or help them choose among alternative actions. To evaluate the success of such communications, a definition of "understanding" is needed. This paper suggests that decisions about personal risks require, at a minimum, information about the nature and likelihood of potential ill effects, information about the risk factors that modify one's susceptibility, and information about the ease or difficulty of avoiding harm. Even if these attributes are accepted as essential criteria for understanding, research on risk perceptions suggests that assessing what people know or believe is sometimes quite difficult. The focus of the paper is on the several dimensions of risk comprehension. Examples of how each can be assessed are drawn from research on public perceptions of the risks from smoking. These examples demonstrate that the public has only a limited understanding of smoking risks.

Experimental evidence for stages of health behavior change: the precaution adoption process model applied to home radon testing.

Hypotheses generated by the precaution adoption process model, a stage model of health behavior, were tested in the context of home radon testing. The specific idea tested was that the barriers impeding progress toward protective action change from stage to stage. An intervention describing a high risk of radon problems in study area homes was designed to encourage homeowners in the model's undecided stage to decide to test, and a low-effort, how-to-test intervention was designed to encourage homeowners in the decided-to-act stage to order test kits. Interventions were delivered in a factorial design that created conditions matched or mismatched to the recipient's stage (N = 1,897). Both movement to a stage closer to testing and purchase of radon test kits were assessed. As predicted, the risk treatment was relatively more effective in getting undecided people to decide to test than in getting decided-to-act people to order a test. Also supporting predictions, the low-effort intervention proved relatively more effective in getting decided-to-act people to order tests than in getting undecided people to decide to test.

Stage theories of health behavior: conceptual and methodological issues.

Despite growing interest in stage theories of health behavior, there is considerable confusion in the literature concerning the essential characteristics of stage theories and the manner in which such theories should be tested. In this article, the 4 key characteristics of a stage theory-a category system, an ordering of categories, similar barriers to change within categories, and different barriers to change between categories--are discussed in detail. Examples of stage models of health behavior also are described. Four major types of research designs that might be used for testing stage theories are examined, including examples from the empirical literature. The most commonly used design, which involves cross-sectional comparisons of people believed to be in different stages, is shown to have only limited value for testing whether behavior change follows a stage process.

Accuracy of smokers' risk perceptions.

In response to disagreements about the extent to which smokers recognize the full risk of smoking-induced illness, an attempt was made to review all articles that have investigated smokers' risk perceptions. These diverse studies are grouped here into four categories, depending on the type of risk judgment solicited by researchers. This grouping shows that the apparent underestimation or overestimation of risk depends on how risk perceptions are assessed. No single conclusion about the accuracy of smokers' numerical risk estimates is possible since the accuracy depends entirely on the health outcome rated (e.g. lung cancer versus all deaths due to smoking). With other types of risk questions, smokers consistently acknowledge that smoking increases health risks, but they judge the size of these increases to be smaller and less well-established than do non-smokers. Finally, smokers minimize the personal relevance of the risks: they do not believe that they are as much at risk as other smokers of becoming addicted or suffering health effects. The accumulated data indicate that smokers continue to minimize their personal health risks.

Using time intervals between expected events to communicate risk magnitudes.

Because members of the public have difficulty understanding risk presented in terms of odds ratios (e.g. 1 in 1000) and in comparing odds ratios from different hazards, we examined the use of time intervals between expected harmful events to communicate risk. Perceptions of the risk from a hypothetical instance of naturally-occurring, cancer-causing arsenic in drinking water supplies was examined with a sample of 705 homeowners. The risk was described as either 1 in 1000 or 1 in 100,000 and as present in a town of 2000 people or a city of 200,000 people. With these parameters, the time intervals ranged from 1 expected death in 3500 years (1 in 100,000 risk, small town) to 1 death every 4 months (1 in 1000 risk, city). The addition of time intervals to the odds ratios significantly decreased perceived threat and perceived need for action in the small town but did not affect response for the city. These framing effects were nearly as large as a 100-fold difference in actual risk. Instances when this communication approach may be useful are discussed.

Resistance of personal risk perceptions to debiasing interventions.

The tendency to believe that one's own risk is less than that of others may reduce interest in health-protective behaviors. This article describes 4 attempts to reduce such optimistic biases. In Study 1, New Jersey residents (N = 222) were provided with lists of risk factors for several health problems. This manipulation was strengthened in Study 2 by presenting risk factors in such a way that participants (164 undergraduates) might see their own standing as inferior to that of others. In Study 3, risk factors were presented one at a time, and participants (190 undergraduates) incorporated them into a mental image of a high-risk individual. Finally, 374 undergraduates in Study 4 generated lists of personal attributes that they believed increased their risk. Optimistic biases were found in each study, but none of the manipulations reduced these biases consistently. In contrast, conditions using opposite manipulations often exacerbated the biases.

High risk or low: how location on a "risk ladder" affects perceived risk.

Efforts to explain risk magnitude often rely on a "risk ladder" in which exposure levels and associated risk estimates are arrayed with low levels at the bottom and high ones at the top. Two experiments were conducted to test the hypothesis that perceived threat and intended mitigation vary with the location of the subject's assigned level on the risk ladder. Subjects were New Jersey homeowners, asked to assume a particular level of radon or asbestos contamination in their homes, to read a brochure explaining the risk, and then to complete a questionnaire. Both studies found that the difference between an assigned level one-quarter of the way up the ladder and the same level three-quarters of the way up the ladder significantly affected threat perception; the effect on mitigation intentions was significant in only one of the studies. Variations in assigned risk also affected threat perception and mitigation intentions. Variations in test magnitude (e.g., 15 fibers per liter vs. 450 fibers per cubic foot, roughly equivalent risks) had no effect, nor did the distinction between radon and asbestos affect the dependent variables. These findings suggest that communicators can design risk ladders to emphasize particular risk characteristics.

Testing four competing theories of health-protective behavior.

Four competing theories of health-protective behavior are reviewed: the health belief model, the theory of reasoned action, protection motivation theory, and subjective expected utility theory. In spite of their commonalities, these models are seldom tested against one another. The review points out the similarities and differences among these theories and the data and analyses needed to compare them. In addition to describing the content of the models, their conceptualization of key variables, and the combinatorial rules used to make predictions, some general problems in theory development and testing for health behaviors are examined. The article's goal is to help investigators design studies that will clarify the strengths and weaknesses of these models, leading toward a better understanding of health behavior.

Correct and incorrect interpretations of correlations between risk perceptions and risk behaviors.

Correlations between risk perceptions and risk behaviors are used by investigators to answer 2 important and easily confused questions: Are individuals' perceptions of their personal risk accurate, correctly reflecting their precautions and their risk-increasing behaviors? and Does recognition of high personal risk cause people to adopt precautions to reduce that risk? Researchers who use survey data to investigate these questions often look at the wrong correlations to get their answers. Furthermore, as members of a population adopt precautions and change their risk status, correlations between perceived risk and risk behavior in this population also change. A mathematical model of precaution adoption--allowing a bidirectional relationship between perception and behavior--is used to illustrate the different correlations between risk perception and risk behavior that can be examined and the changes in correlations that can occur with the passage of time. Recommendations are provided concerning the correlations most appropriate for answering each of the 2 preceding questions. Which correlation is appropriate to answer the second question varies depending on whether a study is begun before people have taken precautions or after ample time to take precautions has already passed.

Scales for assessing perceptions of health hazard susceptibility.

Two studies examined the effectiveness of a variety of commonly used likelihood scales (dichotomous scale, five-point verbally-labeled scale, odds scale, percentage scale, etc.) for assessing perceptions of personal susceptibility to health and safety risks. Two direct evaluation criteria (subjects' ratings of how easy it was to use a scale and of how well the scale reflected their feelings) and three additional measures of validity and reliability (the agreement of scale-derived ranks with a direct ranking, the magnitude of correlations between risk perceptions and appropriate risk factors, and the stability of scores over time) were used to compare the scales. Increasing the number of scale categories did not necessarily improve performance. In fact, a scale with seven verbally-labeled categories performed as well as or better than other scales on all evaluation criteria. These data may help health education researchers in selecting scales to measure perceptions of susceptibility to harm.

Persuasive conversations between friends about health and safety precautions.

One hundred eighty-five conversations in which a college student attempted to convince a friend to adopt a health or safety precaution were examined. A detailed category coding system was developed to describe the content of such conversations and to answer nine specific questions about these interactions. Among other results, the data showed that subjects spend very little time describing the nature of the harm that might occur and usually speak of protection in dichotomous, all-or-none terms rather than acknowledging degrees of risk. Much time is spent discussing the correct actions to take and the problems faced in carrying out these actions. Initial and 2-month assessments of of persuasiveness found no significant relationships between the presence of specific themes and changes in intentions or behavior. The observed content of these conversations is discussed in relation to current theories of self-protective behavior and likely mechanisms of social influence.

Predictors of home radon testing and implications for testing promotion programs.

Four data sets (total N = 3,329) are examined to identify the predictors of home radon testing. The data, interpreted in terms of a stage model of radon testing behavior, reveal that the variables predicting transitions between stages change as people move from one stage to the next. Thinking about radon testing (vs. never having even considered testing) is best predicted by general radon knowledge and by knowing other people who are concerned or have tested. Once contemplating testing, the decision to test is most closely related to the perceived likelihood of a home radon problem. Finally, there are few differences between people who say they have decided to test and those who have already tested. Instead situational factors--including difficulties in locating and choosing among test kits--appear to constitute the final barrier to testing. The ways in which these findings might assist the design of radon outreach programs are discussed, and specific outreach recommendations are advanced.

A model of the precaution adoption process: evidence from home radon testing.

We present the precaution adoption process model--a stage theory consisting of seven distinct states between ignorance and completed preventive action. The stages are "unaware of the issue," "aware of the issue but not personally engaged," "engaged and deciding what to do," "planning to act but not yet having acted," "having decided not to act," "acting," and "maintenance." The theory asserts that these stages represent qualitatively different patterns of behavior, beliefs, and experience and that the factors that produce transitions between stages vary depending on the specific transition being considered. Data from seven studies of home radon testing are examined to test some of the claims made by this model. Stage theories of protective behavior are contrasted with theories that see precaution adoption in terms of movement along a single continuum of action likelihood.

Perceived susceptibility and self-protective behavior: a field experiment to encourage home radon testing.

Tested in a field experiment (N = 647) the hypothesis that perceptions of personal susceptibility are important in decisions to test one's home for radioactive radon gas. Experimental group subjects received a personal telephone call to tell them they lived in a high-risk area and a personal letter to reinforce the telephone message. After the intervention, experimental subjects were significantly more likely than minimal-treatment subjects to acknowledge the possibility of high radon levels in their homes. Perceptions of susceptibility and illness severity were significantly correlated with orders of radon test kits and with testing intentions. Nevertheless, there were no differences between groups in test orders or intentions. Results are discussed in terms of the difficulty of getting people to acknowledge susceptibility and the factors other than risk perceptions that influence self-protective behavior.

Effects of personal experience on self-protective behavior.

This article seeks to further our understanding of self-protective behavior by examining the effects of a particularly powerful stimulus to action: personal experience. It reviews the effects of automobile accidents on seat belt use, criminal victimization other than rape on individual crime prevention efforts, natural hazards experience on both natural hazards preparedness and compliance with evacuation warnings, and myocardial infarction on smoking. Theories suggesting mechanisms that could link personal experience to behavior are described, and data concerning the effects of experience on some key variables in these theories are discussed. Tentative propositions are offered to resolve the many apparent discrepancies in this literature. These propositions concern the effects of experience on risk perceptions, the influence of experience on risk salience, the specificity of responses to victimization, and the duration of experience effects.