CHAPTER THREE e erceivin g Risks Both risks and benefits have to be considered when seeking to understand what drives some behaviours and why some interventions are more acceptable and successful than others. Social, cultural and economic factors are central to how individuals perceive health risks. Similarly, societal and structural factors can influence which risk control policies are adopted and the impact that interventions can achieve. Preventing risk factors has to be planned within the contert of local society, bearing in mind that the success ofpreventive interventions is only partly a matter of individual circumstances and education. In designing intervention strategies, it cannot automatically be assumed that the diverse groups which make up the general public think in the same way as public health professionals and other risk experts. In addition, estimates of risk and its consequences, presented in scientific terms based on a risk assessment, have to be communicated with particular caution and care. The best way is for well- respected professionals, who are seen to be independent and credible, to make the communications. An atmosphere of trust between the government and all interested parties, in both thepublicand private sectors, is essential ifinterventions are to be adopted and successfully implemented
Perceiving Risks 27 CHAPTER THREE erceiving isks 27 Both risks and benefits have to be considered when seeking to understand what drives some behaviours and why some interventions are more acceptable and successful than others. Social, cultural and economic factors are central to how individuals perceive health risks. Similarly, societal and structural factors can influence which risk control policies are adopted and the impact that interventions can achieve. Preventing risk factors has to be planned within the context of local society, bearing in mind that the success of preventive interventions is only partly a matter of individual circumstances and education. In designing intervention strategies, it cannot automatically be assumed that the diverse groups which make up the general public think in the same way as public health professionals and other risk experts. In addition, estimates of risk and its consequences, presented in scientific terms based on a risk assessment, have to be communicated with particular caution and care. The best way is for wellrespected professionals, who are seen to be independent and credible, to make the communications. An atmosphere of trust between the government and all interested parties, in both the public and private sectors, is essential if interventions are to be adopted and successfully implemented.
PERCEIVING RISKS CHANGING PERCEPTIONS OF RISK iven the research on the global burden of risks to health, together with the analysi that underpins the choice of cost-effective interventions, what lessons have been learned about risk perceptions? For high priority risks, how can we implement more effective risk avoidance and reduction policies in the future? This chapter starts with an overview of how the study of risk analysis has developed since the 1970s. It then draws attention to the need to have a broad perspective on how risks are defined and perceived in society, both by individuals and by different groups. Next, emphasis is given to the importance of improving communications about health risks if successful strategies are to be adopted to control them. However, risk perceptions all over the world are increasingly being influenced by three other trends. First, by the power and influence of special interest groups connected to corporate business interests and the opposition being organized by many advocacy and public health groups. Second, by the increasing influence of the global mass media. And third, by the increase in risk factors within many middle and low income countries as a consequence of the effects of globalization Until recently, risks to health were defined largely from the scientific perspective, even ough it has been recognized for some time that risks are commonly understood and interpreted very differently by different groups in society, such as scientists, professionals, and politicians. Assessment and management of risks to health is a relatively new area of study that has been expanding steadily since the early 1970s.It began by focusing on developing scientific methods for identifying and describing hazards and for assessing the probability of associated adverse outcome events and their onsequences. Particular attention has been given to the type and scale of the adverse consequences, including any likely mortality. In the early years, risk analysis, as it was the called, was seen mainly as a new scientific activity concerned with environmental and other external threats to health, such as chemical exposures, road traffic accidents, and radiation and nuclear power disasters. The early study of risk developed mainly in the USA and During the early 1980s, risk analysis evolved into the two main phases of risk assessment and risk management, as more attention was given to how hazards or risk factors could be controlled at both the individual level and by society as a whole. The emphasis moved from determining the probability of adverse events for different risk factors to assessing the scale
Perceiving Risks 29 CHANGING PERCEPTIONS OF RISK iven the research on the global burden of risks to health, together with the analysis that underpins the choice of cost-effective interventions, what lessons have been learned about risk perceptions? For high priority risks, how can we implement more effective risk avoidance and reduction policies in the future? This chapter starts with an overview of how the study of risk analysis has developed since the 1970s. It then draws attention to the need to have a broad perspective on how risks are defined and perceived in society, both by individuals and by different groups. Next, emphasis is given to the importance of improving communications about health risks if successful strategies are to be adopted to control them. However, risk perceptions all over the world are increasingly being influenced by three other trends. First, by the power and influence of special interest groups connected to corporate business interests and the opposition being organized by many advocacy and public health groups. Second, by the increasing influence of the global mass media. And third, by the increase in risk factors within many middle and low income countries as a consequence of the effects of globalization. Until recently, risks to health were defined largely from the scientific perspective, even though it has been recognized for some time that risks are commonly understood and interpreted very differently by different groups in society, such as scientists, professionals, managers, the general public and politicians. Assessment and management of risks to health is a relatively new area of study that has been expanding steadily since the early 1970s. It began by focusing on developing scientific methods for identifying and describing hazards and for assessing the probability of associated adverse outcome events and their consequences. Particular attention has been given to the type and scale of the adverse consequences, including any likely mortality. In the early years, risk analysis, as it was then called, was seen mainly as a new scientific activity concerned with environmental and other external threats to health, such as chemical exposures, road traffic accidents, and radiation and nuclear power disasters. The early study of risk developed mainly in the USA and Europe (1). During the early 1980s, risk analysis evolved into the two main phases of risk assessment and risk management, as more attention was given to how hazards or risk factors could be controlled at both the individual level and by society as a whole. The emphasis moved from determining the probability of adverse events for different risk factors to assessing the scale 3 PERCEIVING RISKS
The World Health Report 2002 and range of possible consequences. Deaths are commonly seen as one of the most important consequences. Attempts were also made to reduce any uncertainties in making the scientific estimates(2). An important consequence of this change was that individual people were now seen as being mainly responsibility for handling their own risks to health, since many risks were characterized as behavioural in origin and, therefore, largely under individual control. This in turn led to the lifestyles approach in health promotion. For instance, a great deal of attention was paid to combating coronary heart disease through health promotion aimed at high-risk individuals, such as increasing exercise and lowering dietary cholesterol, while policies for combating cigarette smoking also emphasized the importance of individual The need for stronger government regulatory controls also became more apparent, with two other important developments. First, governments in many industrialized countries saw their role as law enforcers and passed legislation to establish new and powerful publ regulatory agencies, such as the Food and Drug Administration(FDA)in the USA and the Health and Safety Executive(HSE)in the United Kingdom. Second, increased attention was given to deriving minimum acceptable exposure levels and the adoption of many new international safety standards, particularly for environmental and chemical risks. This included, for example, risks associated with air pollutants, vehicle emissions, foods and the QUESTIONING THE SCIENCE IN RISK ASSESSMENT The so-called scientifico quantitative approach to health risk assessment aims to produce the best possible numerical estimates of the chance or probability of adverse health outcomes for use in policy-making. Although high credibility is usually given to this approach, how valid is this assumption? Why is this approach often seen as more valid than the judgements made by the public or social scientists? Although risk assessment appears to follow a scientifically logical sequence, in practice there are considerable difficulties in making"objective "decisions at each step in the calculations. Thus the risk modeller has to adopt a specific definition of risk and needs to introduce into the model a series of more subjective judgements and assumptions(3, 4) lany of these include implicit and subjective values, such as the numerical expression fo risk, weighting the value of life at different ages, the discount rates and choice of adverse ealth outcomes to be included. For instance, scientific judgements may be needed on the effects of different levels of exposure or which outcomes to include, particularly which disease episodes should be counted among the adverse events During the 1980s, scientific predictions were seen to be rational, objective and valid, while public perceptions were believed to be largely subjective, ill-informed and, therefore, less valid. This led to risk control policies that attempted to"correct"and"educate"the public in the more valid scientific notions of risk and risk management. However, this approach was increasingly challenged by public interest and pressure groups, which asked scientists to explain their methods and assumptions.These critical challenges often revealed the high levels of scientific uncertainty that were inherent in many calculations. Such groups then became more confident, enabling them to argue strongly for the validity of their own ents and interpretation of risks
30 The World Health Report 2002 and range of possible consequences. Deaths are commonly seen as one of the most important consequences. Attempts were also made to reduce any uncertainties in making the scientific estimates (2). An important consequence of this change was that individual people were now seen as being mainly responsibility for handling their own risks to health, since many risks were characterized as behavioural in origin and, therefore, largely under individual control. This in turn led to the lifestyles approach in health promotion. For instance, a great deal of attention was paid to combating coronary heart disease through health promotion aimed at high-risk individuals, such as increasing exercise and lowering dietary cholesterol, while policies for combating cigarette smoking also emphasized the importance of individual choice. The need for stronger government regulatory controls also became more apparent, with two other important developments. First, governments in many industrialized countries saw their role as law enforcers and passed legislation to establish new and powerful public regulatory agencies, such as the Food and Drug Administration (FDA) in the USA and the Health and Safety Executive (HSE) in the United Kingdom. Second, increased attention was given to deriving minimum acceptable exposure levels and the adoption of many new international safety standards, particularly for environmental and chemical risks. This included, for example, risks associated with air pollutants, vehicle emissions, foods and the use of agricultural chemicals. QUESTIONING THE SCIENCE IN RISK ASSESSMENT The so-called scientific or quantitative approach to health risk assessment aims to produce the best possible numerical estimates of the chance or probability of adverse health outcomes for use in policy-making. Although high credibility is usually given to this approach, how valid is this assumption? Why is this approach often seen as more valid than the judgements made by the public or social scientists? Although risk assessment appears to follow a scientifically logical sequence, in practice there are considerable difficulties in making “objective” decisions at each step in the calculations. Thus the risk modeller has to adopt a specific definition of risk and needs to introduce into the model a series of more subjective judgements and assumptions (3, 4). Many of these include implicit and subjective values, such as the numerical expression for risk, weighting the value of life at different ages, the discount rates and choice of adverse health outcomes to be included. For instance, scientific judgements may be needed on the effects of different levels of exposure or which outcomes to include, particularly which disease episodes should be counted among the adverse events. During the 1980s, scientific predictions were seen to be rational, objective and valid, while public perceptions were believed to be largely subjective, ill-informed and, therefore, less valid. This led to risk control policies that attempted to “correct” and “educate” the public in the more valid scientific notions of risk and risk management. However, this approach was increasingly challenged by public interest and pressure groups, which asked scientists to explain their methods and assumptions. These critical challenges often revealed the high levels of scientific uncertainty that were inherent in many calculations. Such groups then became more confident, enabling them to argue strongly for the validity of their own assessments and interpretation of risks
Perceiving Risks EMERGING IMPORTANCE OF RISK PERCEPTIONS By the early 1990s, particularly in North America and Europe, it became apparent that relying mainly on the scientific approaches to risk assessment and management was not always achieving the expected results. It also became clear that risk had different meanings to different groups of people and that all risks had to be understood within the larger social cultural and economic context (5-7). In addition, people compare health risks with any associated benefits and they are also aware of a wide array of other relevant risks. In fact, it has been argued that concepts of risk are actually embedded within societies and their cultures, which largely determines how individuals perceive risks and the autonomy they may have to control them(8). In addition, it became apparent that public perceptions of risks to health did not necessarily agree with those of the scientists, whose authority was increasingly being questioned by both the general public and politicians. Although there was considerable agreement between the public and scientists on many risk assessments, there were also some, such as nuclear power and pesticides, where there were large differences of opinion(see Box 3. 1). These differences of perception often led to intense public controvers At the same time, there was also increasing disillusionment with the"lifestyles"approach to health promotion and education strategies, that relied on improving the health knowledge and beliefs of individuals. These approaches were not achieving sufficient behavioural change for the interventions to be judged cost-effective. For instance, the rapid emergence of HIv AIdS demonstrated that relying on the health beliefs model for behavioural change was largely ineffective in reducing the high-risk sexual behaviours that increased transmission in the epidemic. In addition, as the general public and special interest groups, particularly those in the environmental movements, became better organized they also began ao) gng the motives of the large corporate businesses, such as the tobacco industry challe By the mid-1990s, improving risk communications was seen as essential for resolving the differences between these various positions, as it became more widely accepted that both the scientific approaches and public perceptions of risk were valid. It was also generally accepted that differences in perceptions of risk had to be understood and resolved. This in turn led to the conclusion that governments and politicians had a major role to play in handling conflicts over risk policies by promoting open and transparent dialogue within society, in order to have high levels of public trust in such dialogue. A very important lesson is that high levels of trust between all parties are essential if reductions in the future globa burden of risks to health are to be achieved(11, 12) Box 3. 1 Perceptions of risk by scientists and the general public "Perhaps the most important message from sation of risk is much richer than that of experts two-way process. Each side, expert and publi research is that there is wisdom as well as and reflects legitimate concerns that are typically has something valid to contribute. Each side error in public attitudes and perceptions. Lay omitted from expert risk assessments. As a result, must respect the insights and intelligence of the people sometimes lack certain information risk communication and risk management efforts other about hazards. However, their basic conceptuali- are destined to fail unless they are structured as a Source: (9).p. 285
Perceiving Risks 31 EMERGING IMPORTANCE OF RISK PERCEPTIONS By the early 1990s, particularly in North America and Europe, it became apparent that relying mainly on the scientific approaches to risk assessment and management was not always achieving the expected results. It also became clear that risk had different meanings to different groups of people and that all risks had to be understood within the larger social, cultural and economic context (5–7). In addition, people compare health risks with any associated benefits and they are also aware of a wide array of other relevant risks. In fact, it has been argued that concepts of risk are actually embedded within societies and their cultures, which largely determines how individuals perceive risks and the autonomy they may have to control them (8). In addition, it became apparent that public perceptions of risks to health did not necessarily agree with those of the scientists, whose authority was increasingly being questioned by both the general public and politicians. Although there was considerable agreement between the public and scientists on many risk assessments, there were also some, such as nuclear power and pesticides, where there were large differences of opinion (see Box 3.1). These differences of perception often led to intense public controversy. At the same time, there was also increasing disillusionment with the “lifestyles” approach to health promotion and education strategies, that relied on improving the health knowledge and beliefs of individuals. These approaches were not achieving sufficient behavioural change for the interventions to be judged cost-effective. For instance, the rapid emergence of HIV/ AIDS demonstrated that relying on the health beliefs model for behavioural change was largely ineffective in reducing the high-risk sexual behaviours that increased transmission in the epidemic. In addition, as the general public and special interest groups, particularly those in the environmental movements, became better organized they also began challenging the motives of the large corporate businesses, such as the tobacco industry (10). By the mid-1990s, improving risk communications was seen as essential for resolving the differences between these various positions, as it became more widely accepted that both the scientific approaches and public perceptions of risk were valid. It was also generally accepted that differences in perceptions of risk had to be understood and resolved. This in turn led to the conclusion that governments and politicians had a major role to play in handling conflicts over risk policies by promoting open and transparent dialogue within society, in order to have high levels of public trust in such dialogue. A very important lesson is that high levels of trust between all parties are essential if reductions in the future global burden of risks to health are to be achieved (11, 12). Box 3.1 Perceptions of risk by scientists and the general public “Perhaps the most important message from this research is that there is wisdom as well as error in public attitudes and perceptions. Lay people sometimes lack certain information about hazards. However, their basic conceptualisation of risk is much richer than that of experts and reflects legitimate concerns that are typically omitted from expert risk assessments. As a result, risk communication and risk management efforts are destined to fail unless they are structured as a two-way process. Each side, expert and public, has something valid to contribute. Each side must respect the insights and intelligence of the other.” Source: (9). p.285
The World Health Report 2002 RISK PERCEPTIONS The assumption made in this report is that risk factors, risk probabilities and adverse events can be defined and measured. This is a valid starting point for the quantification of the adverse effects of a range of risk factors and for health advocacy. However, as we have seen above, when interpreting the global burden of risks to health and using this to design intervention strategies, wider perspectives are needed. Evaluating these risks must take lace within a much broader context. People's risk perceptions are based on a diverse array of information that they have processed on risk factors(sometimes called hazards) and technologies, as well as on their benefits and contexts. For instance, people receive information and form their values based on their past experience, communications from scientific sources and the media, as well as from family, peers and other familiar groups. This transfer and learning from experience also occurs within the context of a persons society and culture, including references to beliefs and systems of meaning. It is through the organization of all this knowledge, starting in early childhood, that individuals perceive and make sense of their world. In a similar way, perceptions of risks to health are embedded within different economic, social and cultural environments Much of the original impetus for research on perceptions came from the pioneering work of Starr (13)in trying to weigh the risks from technologies against their perceived benefits. Empirical studies of individual risk perceptions had their origins mainly in psychological studies conducted in the USA (4, 14). A major early discovery was of a set of mental strategies orrules, also called heuristics, that people use to understand risks(15).An arly approach to study and map people s understanding of risks was to ask them to estimate the number of deaths for 40 different hazards and to compare these with known statistical estimates(16, 17). This showed that people tend to overestimate the number of deaths from rarer and infrequent risks, while underestimating considerably those from common and frequent causes, such as cancers and diabetes. This finding has obvious implications for control strategies that are focused on many common and widely distributed risks to health In addition, rare but vivid causes are even more overestimated. Familiarity and exposure through the mass media tend to reinforce these perceptions. However, people' s rank ordering the total number of deaths does usually correspond well overall with the rank order of official estimates Risk factors have many dimensions, including a variety of benefits, and certainly risk means far more to most people than just the possible number of deaths. Another pioneering research study, which is relevant to the present analysis of global risks to health, used psychometric testing to measure perceptions of 90 different hazards using 18 separat alitative characteristics(18). Following factor analysis these hazards were scaled depending on their degree of"dread"and their degree of"unknown risk"(see Figure 3.1, which shows 20 risks selected from the original 90). A third factor(not shown in the figure)related to the number of people involved. Figure 3. 1 clearly shows that the most highly uncertain risks, ch as nuclear power and pesticides, are the most dreaded, whil nany health interventions and clinical procedures have more acceptable values. For instance, e dread factor levels and the higher the perceived unknown risks, the more people want action to reduce these risks, including through stricter government regulation and legislative perceived risks. Rather, they want stronger controls against many nist of benefits against controls. It appears that people often do not make a simple trade-off
32 The World Health Report 2002 RISK PERCEPTIONS The assumption made in this report is that risk factors, risk probabilities and adverse events can be defined and measured. This is a valid starting point for the quantification of the adverse effects of a range of risk factors and for health advocacy. However, as we have seen above, when interpreting the global burden of risks to health and using this to design intervention strategies, wider perspectives are needed. Evaluating these risks must take place within a much broader context. People’s risk perceptions are based on a diverse array of information that they have processed on risk factors (sometimes called hazards) and technologies, as well as on their benefits and contexts. For instance, people receive information and form their values based on their past experience, communications from scientific sources and the media, as well as from family, peers and other familiar groups. This transfer and learning from experience also occurs within the context of a person’s society and culture, including references to beliefs and systems of meaning. It is through the organization of all this knowledge, starting in early childhood, that individuals perceive and make sense of their world. In a similar way, perceptions of risks to health are embedded within different economic, social and cultural environments. Much of the original impetus for research on perceptions came from the pioneering work of Starr (13) in trying to weigh the risks from technologies against their perceived benefits. Empirical studies of individual risk perceptions had their origins mainly in psychological studies conducted in the USA (4, 14). A major early discovery was of a set of mental strategies or rules, also called heuristics, that people use to understand risks (15). An early approach to study and map people’s understanding of risks was to ask them to estimate the number of deaths for 40 different hazards and to compare these with known statistical estimates (16, 17). This showed that people tend to overestimate the number of deaths from rarer and infrequent risks, while underestimating considerably those from common and frequent causes, such as cancers and diabetes. This finding has obvious implications for control strategies that are focused on many common and widely distributed risks to health. In addition, rare but vivid causes are even more overestimated. Familiarity and exposure through the mass media tend to reinforce these perceptions. However, people’s rank ordering by the total number of deaths does usually correspond well overall with the rank order of official estimates. Risk factors have many dimensions, including a variety of benefits, and certainly risk means far more to most people than just the possible number of deaths. Another pioneering research study, which is relevant to the present analysis of global risks to health, used psychometric testing to measure perceptions of 90 different hazards using 18 separate qualitative characteristics (18). Following factor analysis these hazards were scaled depending on their degree of “dread” and their degree of “unknown risk”(see Figure 3.1, which shows 20 risks selected from the original 90). A third factor (not shown in the figure) related to the number of people involved. Figure 3.1 clearly shows that the most highly uncertain risks, such as nuclear power and pesticides, are the most dreaded, while risks associated with many health interventions and clinical procedures have more acceptable values. For instance, antibiotics, anaesthetics, childbirth and surgery are perceived as being much safer. The higher the dread factor levels and the higher the perceived unknown risks, the more people want action to reduce these risks, including through stricter government regulation and legislative controls. It appears that people often do not make a simple trade-off of benefits against perceived risks. Rather, they want stronger controls against many risks
Perceiving Risks Risks that are both highly uncertain and highly dreaded are also clearly the most diffi- cult to predict and control. Two very important factors for dread were found to be global catastrophe and risks that involve members of future generations. The advent of glol terrorism and the development of genetically modified foods are two recent examples.Less dreaded risks tend to be those that are individual, controllable and easily reduced. The more acceptable risks are those that are known, observable and have immediate effects. In addition, the more equitable the risks, the more likely they are to be generally accepted. useful to consider perceptions of dread and unknown risk in relation to public health interventions for reducing risks. If risk factors are to be controlled, the interventions should be perceived to have low dread and a low risk of adverse events. Higher risks from such interventions will normally only be accepted by individuals in the higher risk groups However, population-wide interventions to reduce risk typically have to cover all people, even those at low risk. Thus interventions used in public health programmes need to have low dread and known low and acceptable levels of risk, combined with high safety levels. Typically, vaccination and screening programmes fall into this category, particularly as they are usually targeted at whole populations and involve many healthy people who are at low risk of getting ill and dying. The favourable perception of the public to prescribed medicines, for example, has been attributed to the direct benefits of such medicines and to the trust people place in their safety, achieved through research and testing carried out by medical and pharmaceutical professionals Figure 3. 1 Hazards for dread and riska not observable unknown to those exposed effect delayed risks unknown to science Food irradiation◆ Oral contraceptives Low dread risk Vaccinations. High dread risk controllable uncontrollable Pregnancy, childbirth. Surgery Alcoholic beverages◆ own risk risks known to science from interrelationships of 18 risk characteristics. Fador 3 (not shown)reflects the number of people exposed to the hazard and the degree of their personal exposure
Perceiving Risks 33 Risks that are both highly uncertain and highly dreaded are also clearly the most difficult to predict and control. Two very important factors for dread were found to be global catastrophe and risks that involve members of future generations. The advent of global terrorism and the development of genetically modified foods are two recent examples. Less dreaded risks tend to be those that are individual, controllable and easily reduced. The more acceptable risks are those that are known, observable and have immediate effects. In addition, the more equitable the risks, the more likely they are to be generally accepted. It is useful to consider perceptions of dread and unknown risk in relation to public health interventions for reducing risks. If risk factors are to be controlled, the interventions should be perceived to have low dread and a low risk of adverse events. Higher risks from such interventions will normally only be accepted by individuals in the higher risk groups. However, population-wide interventions to reduce risk typically have to cover all people, even those at low risk. Thus interventions used in public health programmes need to have low dread and known low and acceptable levels of risk, combined with high safety levels. Typically, vaccination and screening programmes fall into this category, particularly as they are usually targeted at whole populations and involve many healthy people who are at low risk of getting ill and dying. The favourable perception of the public to prescribed medicines, for example, has been attributed to the direct benefits of such medicines and to the trust people place in their safety, achieved through research and testing carried out by medical and pharmaceutical professionals. Food irradiation Lasers Nuclear power Water fluoridation Oral contraceptives Asbestos Radiation therapy Pesticides Diagnostic X-rays Vaccinations Antibiotics Anaesthetics Smoking Pregnancy, childbirth Surgery Alcoholic beverages Open-heart surgery Morphine Nerve gas Terrorism Low dread risk - controllable - not dreaded - not global catastrophic - consequences not fatal - equitable - individual - low risk to future generations - easily reduced - risk decreasing - voluntary - doesn't affect me Known risk - observable - known to those exposed - effect immediate - old risk - risks known to science Unknown risk - not observable - unknown to those exposed - effect delayed - new risk - risks unknown to science High dread risk - uncontrollable - dreaded - global catastrophic - consequences not fatal - not equitable - catastrophic - high risk to future generations - not easily reduced - risk increasing - involuntary - affects me Figure 3.1 Hazards for dread and riska a Adapted from: Slovic P, Fischhoff B, Lichtenstein S. Facts and fears: understanding perceived risk. In: Schwing RC, Albers WA Jr, editors. Societal risk assessment: how safe is safe enough? New York: Plenum; 1980. Locations of 20 hazards – instead of 90 in the original – on factor 1 (dread) and factor 2 (unknown risk) of the three-dimensional figure derived from interrelationships of 18 risk characteristics. Factor 3 (not shown) reflects the number of people exposed to the hazard and the degree of their personal exposure
The World Health Report 2002 DEFINING AND DESCRIBING RISKS TO HEALTH Risk assessment and management is a political as well as a scientific process, and public perceptions of risk and risk factors involve values and beliefs, as well as power and trust For policy-makers who are promoting intervention strategies to lower risks to health, it is obviously important, therefore, to understand the different ways in which the general public and health professionals perceive risks(19). As described in Chapter 2, use of the term"risk has many different meanings and this often causes difficulties in communication. This report uses the notions of the probability of a subsequent adverse health event, followed by its consequence which is mainly either morbidity or mortality While many scientists often assume that risks can be objectively verified, many social scientists argue that risk measures are inherently much more subjective. In addition, other members of the public have yet other notions of risk. How do people define and describe risk factors? How do they estimate risks? Answers to such questions obviously alter people's perceptions. Such information is needed, therefore, to improve communications and to predict public responses to public health interventions, including the introduction of new health technologies and risk factor and disease prevention programmes. Box 3. 2 illustrates male perceptions of sexual health risks and the need to use preventive measures against HIV infection and pregnancy A complicated question is how the mortality outcome associated with a particular risk factor should be expressed Even choosing or framing the end-point as death is surprising omplex and can make large differences in the way risk is both perceived and evaluated The following is a well-known example from occupational health, which shows how the choice of risk measure can make a technology appear less or more risky to health(21) Between 1950 and 1970, coal mining in the USa became much less risky if the measure of risk was taken to be accident deaths per million tons of coal produced, but it became more risky if risk was described in terms of accident deaths per 1000 miners employed. Which easure is more appropriate for decision-making? From a national perspective, and given the need to produce coal, deaths of miners per million tons of coal produced appears to be e more appropriate measure of risk. However, from the point of view of individual miners and their trade unions the death rate per thousand miners employed is obviously far more relevant. Since both measures for framing the risks in this industry are relevant, both should e considered in any risk management decision-making process Each way of summarizing deaths embodies its own set of inherent and subjective values (7). For example, an estimate based on reduction in life expectancy treats deaths of young people as more important than deaths of older people, who have less life expectancy to lose. However, counting all fatalities together treats all deaths of the young and old as equivalent. This approach also treats equally deaths immediately after mishaps and deaths that follow painful and lengthy debilitating diseases Such choices all involve subjective value judgements. For instance, using"number of deaths "may not distinguish deaths of people who engage in an activity by choice and benefit from it directly, from those of people who are exposed to a hazard involuntarily and who get no direct benefits. Each approach may be justifiable but uses value judgements about which deaths are considered to be the most undesirable. To overcome such problems, information should be framed in a variety of different ways so that such complexities are revealed to decision-makers
34 The World Health Report 2002 DEFINING AND DESCRIBING RISKS TO HEALTH Risk assessment and management is a political as well as a scientific process, and public perceptions of risk and risk factors involve values and beliefs, as well as power and trust. For policy-makers who are promoting intervention strategies to lower risks to health, it is obviously important, therefore, to understand the different ways in which the general public and health professionals perceive risks (19). As described in Chapter 2, use of the term “risk” has many different meanings and this often causes difficulties in communication. This report uses the notions of the probability of a subsequent adverse health event, followed by its consequence which is mainly either morbidity or mortality. While many scientists often assume that risks can be objectively verified, many social scientists argue that risk measures are inherently much more subjective. In addition, other members of the public have yet other notions of risk. How do people define and describe risk factors? How do they estimate risks? Answers to such questions obviously alter people’s perceptions. Such information is needed, therefore, to improve communications and to predict public responses to public health interventions, including the introduction of new health technologies and risk factor and disease prevention programmes. Box 3.2 illustrates male perceptions of sexual health risks and the need to use preventive measures against HIV infection and pregnancy. A complicated question is how the mortality outcome associated with a particular risk factor should be expressed. Even choosing or framing the end-point as death is surprisingly complex and can make large differences in the way risk is both perceived and evaluated. The following is a well-known example from occupational health, which shows how the choice of risk measure can make a technology appear less or more risky to health (21). Between 1950 and 1970, coal mining in the USA became much less risky if the measure of risk was taken to be accident deaths per million tons of coal produced, but it became more risky if risk was described in terms of accident deaths per 1000 miners employed. Which measure is more appropriate for decision-making? From a national perspective, and given the need to produce coal, deaths of miners per million tons of coal produced appears to be the more appropriate measure of risk. However, from the point of view of individual miners and their trade unions the death rate per thousand miners employed is obviously far more relevant. Since both measures for framing the risks in this industry are relevant, both should be considered in any risk management decision-making process. Each way of summarizing deaths embodies its own set of inherent and subjective values (7). For example, an estimate based on reduction in life expectancy treats deaths of young people as more important than deaths of older people, who have less life expectancy to lose. However, counting all fatalities together treats all deaths of the young and old as equivalent. This approach also treats equally deaths immediately after mishaps and deaths that follow painful and lengthy debilitating diseases. Such choices all involve subjective value judgements. For instance, using “number of deaths” may not distinguish deaths of people who engage in an activity by choice and benefit from it directly, from those of people who are exposed to a hazard involuntarily and who get no direct benefits. Each approach may be justifiable but uses value judgements about which deaths are considered to be the most undesirable. To overcome such problems, information should be framed in a variety of different ways so that such complexities are revealed to decision-makers
Perceiving Risks Box 3. 2 Men's sexual behaviour related to risk of HIv infection and pregnancy a greater understanding of mens female partners. Samples of 750-850 men were prostitutes, strangers and lovers, but erceptions of sexual risk and their risk-taking selected randomly in each city. The percentages considerably less so with married partners behaviour is necessary if interventions are to be who reported having taken preventive measures However, just over half the young men said they more successful in improving the reproductive -usually the use of condoms -to reduce the risk would use such measures when having health of both men and women. In a question- of HIv transmission or pregnancy are shown intercourse with a virgin or a fiancee. The need naire survey of reproductive risk behaviours in below. measures to prevent pregna the capital cities of Argentina, Bolivia, Cuba and The findings were very similar in all four cities, perceived, however, to be higher than that for Peru, young adult males(aged 20-29 years) were though the men clearly perceived the risks as HIv infection. To avoid pregnancy, such measures asked whether they would take measures to being different with different partners. Preventive were commonly used with all sexual partners prevent HIV infection and pregnancy during measures against HIv infection were believed to and even with about half the spouses sexual intercourse with different categories of be highly necessary for sexual intercourse with Perceived sexual health risk, 20-29-year-old men Buenos Aires La paz Havana Sexual partnerArgentina Cuba Prostitute 100%0% spondents who took preventive measures against HIv infection(%) pondents who took preventive measures against pregnancy(%) INFLUENCES ON RISK PERCEPTIONS Two important factors that influence risk perception are gender and world views, with filiation, emotional affect and trust also being strongly correlated with the risk judgements of experts as well as lay persons. The influence of gender has been well documented, with men tending to judge risks as smaller and less problematic than do women. Explanations have focused mainly on biological and social factors. For example, it has been suggested that women are more socialized to care for human health and are less likely to be familiar with science and technology. However, female toxicologists were found to judge the same risks as higher than do male toxicologists(22, 23). In another study dealing with perception of 25 hazards, males produced risk-perception ratings that were consistently much lower of risks, gender differences appear to have an important effect on interpretingris Option than those of females(24). To the extent that sociopolitical factors shape public perce The influence of social, psychological and political factors can also be seen in studies on the impact of world views on risk judgements. World views are general social, cultural and political attitudes that appear to have an influence over people' s judgements about complex issues(25). World views include feelings such as fatalism towards control over risks to health, belief in hierarchy and leaving decisions to the experts, and a conviction that individualism is an important characteristic of a fair society, or that technological developments are important for improving our health and social well-being. These world views have been found to be strongly linked to public perceptions of risk (26). These views have also been
Perceiving Risks 35 INFLUENCES ON RISK PERCEPTIONS Two important factors that influence risk perception are gender and world views, with affiliation, emotional affect and trust also being strongly correlated with the risk judgements of experts as well as lay persons. The influence of gender has been well documented, with men tending to judge risks as smaller and less problematic than do women. Explanations have focused mainly on biological and social factors. For example, it has been suggested that women are more socialized to care for human health and are less likely to be familiar with science and technology. However, female toxicologists were found to judge the same risks as higher than do male toxicologists (22, 23). In another study dealing with perception of 25 hazards, males produced risk-perception ratings that were consistently much lower than those of females (24). To the extent that sociopolitical factors shape public perception of risks, gender differences appear to have an important effect on interpreting risks. The influence of social, psychological and political factors can also be seen in studies on the impact of world views on risk judgements. World views are general social, cultural and political attitudes that appear to have an influence over people’s judgements about complex issues (25). World views include feelings such as fatalism towards control over risks to health, belief in hierarchy and leaving decisions to the experts, and a conviction that individualism is an important characteristic of a fair society, or that technological developments are important for improving our health and social well-being. These world views have been found to be strongly linked to public perceptions of risk (26). These views have also been Box 3.2 Men’s sexual behaviour related to risk of HIV infection and pregnancy A greater understanding of men’s perceptions of sexual risk and their risk-taking behaviour is necessary if interventions are to be more successful in improving the reproductive health of both men and women. In a questionnaire survey of reproductive risk behaviours in the capital cities of Argentina, Bolivia, Cuba and Peru, young adult males (aged 20–29 years) were asked whether they would take measures to prevent HIV infection and pregnancy during sexual intercourse with different categories of prostitutes, strangers and lovers, but considerably less so with married partners. However, just over half the young men said they would use such measures when having intercourse with a virgin or a fiancée. The need for measures to prevent pregnancy was perceived, however, to be higher than that for HIV infection. To avoid pregnancy, such measures were commonly used with all sexual partners and even with about half the spouses. female partners. Samples of 750–850 men were selected randomly in each city. The percentages who reported having taken preventive measures – usually the use of condoms – to reduce the risk of HIV transmission or pregnancy are shown below. The findings were very similar in all four cities, though the men clearly perceived the risks as being different with different partners. Preventive measures against HIV infection were believed to be highly necessary for sexual intercourse with Source: (20). Buenos Aires Argentina La Paz Sexual partner Bolivia respondents who took preventive measures against HIV infection (%) respondents who took preventive measures against pregnancy (%) Stranger Virgin 0% 50% 100% Prostitute 0% 50% 100% Fiancée Spouse Lover 0% 50% 100% 0% 50% 100% Perceived sexual health risk, 20–29-year-old men Havana Cuba Lima Peru
The World Health Report 2002 the subject of a few international studies, for example comparing perceptions of risks to nuclear power in the USA with those in other industrialized countries (27) FRAMING THE INFORMATION ON RISKS After defining a particular risk problem, determining which people are at risk, measur- to exposure levels and selecting the risk outcomes, all this information has to be presented lecision-makers. How the information is presented usually depends on whether it is meant to influence individuals or national policy-makers. The way the information is pre- sented is often referred to as"framing"(see Box 3.3) Numerous research studies have demonstrated that different but logically equivalent ways of presenting the same risk information can lead to different evaluations and decision A famous example is the study which asked people to imagine that they had lung cancer and had to choose either surgery or radiation therapy(29). The choices were strikingly different, depending on whether the results of treatment were framed as the probability of surviving for varying lengths of time after the treatment or in terms of the probability of dying. When the same results were framed in terms of dying, the choice of radiation therapy over surgery increased from 18%to 44%. The effect was just as strong for physicians as for la All presentations of risk information use frames that can exert a strong influence on decision-makers. However, if all information is equally correct, there are really no"right"or "wrong frames-just different frames. How risk information is framed and communicated to individuals or policy-makers, scientists or the general public can be of crucial importance in achieving maximum influence over public perceptions. It can also be very important in convincing the public health community and high-level policy-makers about the impor tance of risks to health and the value of adopting different interventions SOCIAL AND CULTURAL INTERPRETATIONS OF RISK While the cognitive psychological approach has been very influential, it has also been criticized for concentrating too much on individual perceptions and interpretations of risk. Some psychologists, anthropologists and sociologists have argued that, since individuals are not free agents, risks can best be understood as a social construct within particular within groups and institutions, not only at the individual level (8).These disciplines start from the belief that risks should not be treated independently and separately from the complex social, cultural, economic and political circumstances in Box 3.3 Framing risks to health: choosing presentations Positive or negative framing? Striking changes in preference ca Whole numbers or an analogy? Whole numbers may be less well from framing the risk in either positive or negative terms, such understood than an example or analogy for the size of an adverse event. saved or lives lost, rates of survival or mortality, mproving good health or Small or large numbers? A small number of deaths is more easily ducing risks of disease. understood than a large number, which is often incomprehensible. Relative or absolute risks? Although relative risks are usually better. Short or long periods? A few deaths at one time or over a short period, as nderstood, it can be very important to present absolute changes as well. in a tragic accident, often have more impact than a larger number of Percentages or whole numbers? Probabilities are better understood as deaths occurring discretely over a longer period of time percentage changes than by comparison of whole numbers Source: (28)
36 The World Health Report 2002 the subject of a few international studies, for example comparing perceptions of risks to nuclear power in the USA with those in other industrialized countries (27). FRAMING THE INFORMATION ON RISKS After defining a particular risk problem, determining which people are at risk, measuring exposure levels and selecting the risk outcomes, all this information has to be presented to decision-makers. How the information is presented usually depends on whether it is meant to influence individuals or national policy-makers. The way the information is presented is often referred to as “framing”(see Box 3.3). Numerous research studies have demonstrated that different but logically equivalent ways of presenting the same risk information can lead to different evaluations and decisions. A famous example is the study which asked people to imagine that they had lung cancer and had to choose either surgery or radiation therapy (29). The choices were strikingly different, depending on whether the results of treatment were framed as the probability of surviving for varying lengths of time after the treatment or in terms of the probability of dying. When the same results were framed in terms of dying, the choice of radiation therapy over surgery increased from 18% to 44%. The effect was just as strong for physicians as for lay persons. All presentations of risk information use frames that can exert a strong influence on decision-makers. However, if all information is equally correct, there are really no “right” or “wrong”frames – just different frames. How risk information is framed and communicated to individuals or policy-makers, scientists or the general public can be of crucial importance in achieving maximum influence over public perceptions. It can also be very important in convincing the public health community and high-level policy-makers about the importance of risks to health and the value of adopting different interventions. SOCIAL AND CULTURAL INTERPRETATIONS OF RISK While the cognitive psychological approach has been very influential, it has also been criticized for concentrating too much on individual perceptions and interpretations of risk. Some psychologists, anthropologists and sociologists have argued that, since individuals are not free agents, risks can best be understood as a social construct within particular historical and cultural contexts and within groups and institutions, not only at the individual level (8). These disciplines start from the belief that risks should not be treated independently and separately from the complex social, cultural, economic and political circumstances in Box 3.3 Framing risks to health: choosing presentations • Positive or negative framing? Striking changes in preference can result from framing the risk in either positive or negative terms, such as lives saved or lives lost, rates of survival or mortality, improving good health or reducing risks of disease. • Relative or absolute risks? Although relative risks are usually better understood, it can be very important to present absolute changes as well. • Percentages or whole numbers? Probabilities are better understood as percentage changes than by comparison of whole numbers. • Whole numbers or an analogy? Whole numbers may be less well understood than an example or analogy for the size of an adverse event. • Small or large numbers? A small number of deaths is more easily understood than a large number, which is often incomprehensible. • Short or long periods? A few deaths at one time or over a short period, as in a tragic accident, often have more impact than a larger number of deaths occurring discretely over a longer period of time. Source: (28)
Perceiving Risks which people experience them( 30, 31). Different groups of people appear to identify differ- ent risks, as well as different attributes, depending on the form of social organization and the wider political culture to which they belong (32) Although it is widely accepted that the political and economic situation at a macrolevel is a strong determinant for many risk factors, microlevel studies can examine how such factors are perceived and interpreted rationally within a given local context. Microlevel studies can also be very useful in explaining certain apparent behaviours that do not appear to be rational to the"external"public health observer For instance, although lay people may be well aware of risk factors for coronary heart disease, they also have their own"good"and rational reasons for not following expert advice on prevention(33). Thus the context in which people find themselves also largely determines the constraints they face in trying to avoid risks and the length of time over which risk can be discounted. It is an irony, however, that people living in wealthy and safer societies, with their high living standards and longer life expectancy, appear to be even more highly concerned about risks to health than people living in poorer and less safe communities. This is particularly the case with highly uncertain and highly dreaded risks From the cultural perspective, therefore, the type and kind of risks, as well as a ability to cope with them, will vary according to the individuals wider context. For instance, risk perceptions and their importance can vary between developing and developed countries, as well as with such variables as sex, age, household income, faith and cultural groups, urban and rural areas, and geographical location and climate(for example, see Box 3. 4) PERCEPTIONS OF HEALTH RISKS I DEVELOPING COUNTRIES Risks to health, as an area for further study, have only recently begun to receive attention in developing countries. The need to view such risks in their local context is obvious when analysing perceptions of risk in these countries, especially when risk factors are considered alongside life-threatening diseases such as tuberculosis, malaria and HVIAIDS.There are also other daily threats, such as poverty, food insecurity and lack of income. In addition, families may face many other important"external"risks, such as political instability, violence, atural disasters and wars. Thus every day there is a whole array of risks that have to be considered by individuals and families Models of individual risk perception and behaviour were, however, mainly developed industrialized countries where people have considerably higher personal autonomy and freedom to act, better access to health information, and more scope for making choices for better health. These models may be less appropriate in low and middle income countries, where illnesses and deaths are closely associated with poverty and infectious and communicable diseases(35). In industrialized countries, studies of HivIAIDS and to a lesser extent, noncommunicable diseases such as cancer(5) and coronary heart disease (33)have been carried out using the perspectives of applied medical anthropology and sociology(36). However, in developing countries where communicable diseases still cause a high proportion of the avoidable mortality, these disciplines have most frequently been coopted to help evaluate the effectiveness of disease control programmes. Perceptions of disease, use of health services and reasons for non-compliance are some areas often studie For communicable diseases, it is important to differentiate perceptions of the disease from those concerned with the risk of acquiring the infection, particularly as not all
Perceiving Risks 37 which people experience them (30, 31). Different groups of people appear to identify different risks, as well as different attributes, depending on the form of social organization and the wider political culture to which they belong (32). Although it is widely accepted that the political and economic situation at a macrolevel is a strong determinant for many risk factors, microlevel studies can examine how such factors are perceived and interpreted rationally within a given local context. Microlevel studies can also be very useful in explaining certain apparent behaviours that do not appear to be rational to the “external” public health observer. For instance, although lay people may be well aware of risk factors for coronary heart disease, they also have their own “good” and rational reasons for not following expert advice on prevention (33). Thus the context in which people find themselves also largely determines the constraints they face in trying to avoid risks and the length of time over which risk can be discounted. It is an irony, however, that people living in wealthy and safer societies, with their high living standards and longer life expectancy, appear to be even more highly concerned about risks to health than people living in poorer and less safe communities. This is particularly the case with highly uncertain and highly dreaded risks. From the cultural perspective, therefore, the type and kind of risks, as well as a person’s ability to cope with them, will vary according to the individual’s wider context. For instance, risk perceptions and their importance can vary between developing and developed countries, as well as with such variables as sex, age, household income, faith and cultural groups, urban and rural areas, and geographical location and climate (for example, see Box 3.4). PERCEPTIONS OF HEALTH RISKS IN DEVELOPING COUNTRIES Risks to health, as an area for further study, have only recently begun to receive attention in developing countries. The need to view such risks in their local context is obvious when analysing perceptions of risk in these countries, especially when risk factors are considered alongside life-threatening diseases such as tuberculosis, malaria and HIV/AIDS. There are also other daily threats, such as poverty, food insecurity and lack of income. In addition, families may face many other important “external”risks, such as political instability, violence, natural disasters and wars. Thus every day there is a whole array of risks that have to be considered by individuals and families. Models of individual risk perception and behaviour were, however, mainly developed in industrialized countries where people have considerably higher personal autonomy and freedom to act, better access to health information, and more scope for making choices for better health. These models may be less appropriate in low and middle income countries, where illnesses and deaths are closely associated with poverty and infectious and communicable diseases (35). In industrialized countries, studies of HIV/AIDS and, to a lesser extent, noncommunicable diseases such as cancer (5) and coronary heart disease (33) have been carried out using the perspectives of applied medical anthropology and sociology (36). However, in developing countries where communicable diseases still cause a high proportion of the avoidable mortality, these disciplines have most frequently been coopted to help evaluate the effectiveness of disease control programmes. Perceptions of disease, use of health services and reasons for non-compliance are some areas often studied (37). For communicable diseases, it is important to differentiate perceptions of the risk of a disease from those concerned with the risk of acquiring the infection, particularly as not all