Wendy Nelson

How Numeracy Influences Risk Comprehension and Medical Decision Making

We review the growing literature on health numeracy, the ability to understand and use numerical information, and its relation to cognition, health behaviors, and medical outcomes. Despite the surfeit of health information from commercial and noncommercial sources, national and international surveys show that many people lack basic numerical skills that are essential to maintain their health and make informed medical decisions. Low numeracy distorts perceptions of risks and benefits of screening, reduces medication compliance, impedes access to treatments, impairs risk communication (limiting prevention efforts among the most vulnerable), and, based on the scant research conducted on outcomes, appears to adversely affect medical outcomes. Low numeracy is also associated with greater susceptibility to extraneous factors (i.e., factors that do not change the objective numerical information). That is, low numeracy increases susceptibility to effects of mood or how information is presented (e.g., as frequencies vs. percentages) and to biases in judgment and decision making (e.g., framing and ratio bias effects). Much of this research is not grounded in empirically supported theories of numeracy or mathematical cognition, which are crucial for designing evidence-based policies and interventions that are effective in reducing risk and improving medical decision making. To address this gap, we outline four theoretical approaches (psychophysical, computational, standard dual-process, and fuzzy trace theory), review their implications for numeracy, and point to avenues for future research.

Clinical Implications of Numeracy: Theory and Practice

BackgroundLow numeracy is pervasive and constrains informed patient choice, reduces medication compliance, limits access to treatments, impairs risk communication, and affects medical outcomes; therefore, it is incumbent upon providers to minimize its adverse effects.PurposeWe provide an overview of research on health numeracy and discuss its implications in clinical contexts.ConclusionsLow numeracy cannot be reliably inferred on the basis of patients’ education, intelligence, or other observable characteristics. Objective and subjective assessments of numeracy are available in short forms and could be used to tailor health communication. Low scorers on these assessments are subject to cognitive biases, irrelevant cues (e.g., mood), and sharper temporal discounting. Because prevention of the leading causes of death (e.g., cancer and cardiovascular disease) depends on taking action now to prevent serious consequences later, those low in numeracy are likely to require more explanation of risk to engage in prevention behaviors. Visual displays can be used to make numerical relations more transparent, and different types of displays have different effects (e.g., greater risk avoidance). Ironically, superior quantitative processing seems to be achieved by focusing on qualitative gist and affective meaning, which has important implications for empowering patients to take advantage of the evidence in evidence-based medicine.

Rethinking the Objectives of Decision Aids: A Call for Conceptual Clarity

Health decision aids are a potentially valuable adjunct to patient-physician communication and decision making. Although the overarching goal of decision aids— to help patients make informed, preference-sensitive choices—is widely accepted, experts do not agree on the means to achieve this end. In this article, the authors critically examine the theoretical basis and appropriateness of 2 widely accepted criteria used to evaluate decision aids: values clarification and reduction of decisional conflict. First, they argue that although clarifying values is central to decision making under uncertainty, it is not clear that decision aids—as they have been conceived and operationalized so far—can and should be used to achieve this goal. The pursuit of clarifying values, particularly values clarification exercises, raises a number of ethical, methodological, and conceptual issues, and the authors suggest research questions that should be addressed before values clarification is routinely endorsed. Second, the authors argue that the goal of reducing decisional conflict is conceptually untenable and propose that it be eliminated as an objective of decision aids.

Adherence to Cervical Cancer Screening Guidelines for U.S. Women Aged 25–64: Data from the 2005 Health Information National Trends Survey (HINTS)

BACKGROUND Although it is widely accepted that Papanicolaou (Pap) screening can reduce cervical cancer mortality, many women still do not maintain regular cervical cancer screenings. OBJECTIVE To describe the prevalence of cervical cancer screening and the demographic, behavioral, psychological, and cancer-related knowledge factors associated with adherence to U.S. Preventive Services Task Force (USPSTF) cervical cancer screening guidelines among women in the United States. METHODS Data for women aged 25-64 were obtained from the National Cancer Institutes (NCI) 2005 Health Information National Trends Survey (HINTS). Women were considered adherent to screening guidelines if they had two consecutive, on-schedule screenings and planned to have another within the next 3 years. The sample comprised 2070 women. RESULTS Ninety-eight percent of women reported ever having a Pap smear, 90% reported having had a recent Pap smear (within 3 years), and 84% were adherent to USPSTF screening guidelines. Maintaining regular cervical cancer screening was significantly associated with having health insurance, normal body mass index (BMI), smoking status (nonsmoker), mood (absence of a mood disturbance), and being knowledgeable about cervical cancer screening and human papillomavirus (HPV) infection. CONCLUSIONS Based on the observation that women who were current smokers, obese, or experiencing a substantial degree of psychological distress were significantly less likely to adhere to recommended screening guidelines, we suggest that healthcare providers pay particular attention to the screening needs of these more vulnerable women.

Associations of Perceived Risk and Worry with Cancer Health-protective Actions Data from the Health Information National Trends Survey (HINTS)

This study examined the associations of susceptibility, conceptualized as both a cognition (risk) and as affect (worry) and their possible interaction, with cancer screening behaviors. Data for this study were obtained from the 2003 Health Information National Trends Survey (HINTS). Hierarchical regression models assessed the ability of risk, worry and their interaction (after controlling for other important variables) to predict cancer-screening behaviors. Results found that risk and worry (but not their interaction) were associated with regular mammography screening and having had a sigmoidoscopy or colonoscopy but with neither FOBT nor PSA screening. The findings suggest that risk and worry are both important in predicting some types of screening behavior and that these variables operate independently.

Decision making and cancer.

We review decision making along the cancer continuum in the contemporary context of informed and shared decision making in which patients are encouraged to take a more active role in their health care. We discuss challenges to achieving informed and shared decision making, including cognitive limitations and emotional factors, but argue that understanding the mechanisms of decision making offers hope for improving decision support. Theoretical approaches to decision making that explain cognition, emotion, and their interaction are described, including classical psychophysical approaches, dual-process approaches that focus on conflicts between emotion versus cognition (or reason), and modern integrative approaches such as fuzzy-trace theory. In contrast to the earlier emphasis on rote use of numerical detail, modern approaches emphasize understanding the bottom-line gist of options (which encompasses emotion and other influences on meaning) and retrieving relevant social and moral values to apply to those gist representations. Finally, research on interventions to support better decision making in clinical settings is reviewed, drawing out implications for future research on decision making and cancer.

Basic and Applied Decision Making in Cancer Control

Decision making is fundamental to all aspects of cancer care--prevention, detection, treatment, survivorship, and end of life--yet researchers and clinicians have limited knowledge of the ways in which patients and their health care providers make critical health decisions. Recognizing how important it is to understand how patients and their providers make potentially life-altering decisions, the National Cancer Institute developed a decision making in cancer control initiative. The goal of this initiative is to enhance understanding of human decision-making processes so that individuals can make more informed and satisfying choices regarding their health. This article describes the multidisciplinary meeting that provided the scientific foundation for this initiative.

Exploring Objective and Subjective Numeracy at a Population Level: Findings From the 2007 Health Information National Trends Survey (HINTS)

Numeracy is a critical component of decision making in health, and low numeracy may adversely affect risk comprehension, medical treatment, and health outcomes. Health researchers have developed objective and subjective measures of numeracy that potentially could be used for clinical or health research purposes. To examine the association between objective and subjective numeracy at a population level, data were obtained from the 2007 Health Information National Trends Survey, a health communication survey that collects data from a nationally representative sample of the U.S. population. Associations between items from 2 published subjective numeracy measures (STAT-Confidence Scale; Subjective Numeracy Scale) and a single published objective numeracy measure were examined with respect to one another and with respect to sociodemographic characteristics using a multivariate logistic regression model. Controlling for demographic covariates, both subjective numeracy measures were significantly associated with each other (p < .0001) and with objective numeracy (p < .0001). Compared with respondents who regarded themselves as low in subjective numeracy, those who regarded themselves as high in subjective numeracy had significantly higher odds of answering the objective numeracy question correctly (STAT-Confidence Scale OR = 1.42, CI [1.07, 1.90]; Subjective Numeracy Scale OR = 1.71, CI [1.28, 2.28]). However, the subjective measures performed poorly as diagnostic indicators of objective numeracy. Sensitivity and specificity for the STAT-Confidence Scale and the Subjective Numeracy Scale were 67%/49% and 50%/71%, respectively. More work is needed to elucidate the relation between objective and subjective numeracy, at the conceptual and empirical levels, and to develop more robust measures of subjective numeracy that can better discriminate between individuals with low and high objective numeracy.

Linking decision-making research and cancer prevention and control: Important themes.

This article describes 6 themes underlying the multiple presentations from the Basic and Applied Decision Making in Cancer Control meeting, held February 19-20, 2004. The following themes have important implications for research and practice linking basic decision-making research to cancer prevention and control: (a) Traditional decision-making theories fail to capture real-world decision making, (b) decision makers are often unable to predict future preferences, (c) preferences are often constructed on the spot and thus are influenced by situational cues, (d) decision makers often rely on feelings rather than beliefs when making a decision, (e) the perspective of the decision maker is critical in determining preferences, and (f) informed decision making may--or may not--yield the best decisions.

Precancer Risk Perceptions Predict Postcancer Subjective Well-Being

OBJECTIVE The present study used longitudinal data to explore whether subjective well-being in cancer survivors was related to predisease judgments of their likelihood of getting cancer. METHOD Subjective well-being was assessed in terms of affective well-being (frequency of positive and negative affective states) and satisfaction with ones life overall. The sample consisted of 158 participants in the National Survey of Midlife Development in the U.S. (MIDUS) who developed cancer during the 8-10 years between the first and second waves of the survey (average time since diagnosis = 3.37 years; SD = 2.48), and 3,243 control participants who reported no history of cancer at either wave. RESULTS Controlling for demographic variables and well-being at Wave 1, the effect of cancer on well-being depended on whether, prior to being diagnosed, people judged themselves to be at low or high risk of cancer. For those perceiving a high risk, a cancer diagnosis had a modest but significant negative impact on affect and life satisfaction, whereas no negative impact emerged for those perceiving a low risk. Similar effects were not observed for heart attack risk perceptions, or for measures of trait optimism or depression, suggesting that the effect was domain-specific. CONCLUSIONS Low precancer risk perceptions were associated with long-term benefits for subjective well-being in people who developed cancer.