(2009) showed that this was not always the case. Although the probability and the subjective value of the outcome are usually assumed to be independent constructs, Harris et al. Hence, in health contexts, risk assessment will depend on its probability but also on how severe this risk is considered to be ( Haase et al., 2013). Risks are often conceptualized as a combined function of the probability of a loss and its consequences ( Lipkus, 2007).
Informed consent should be provided after the patient has understood the purpose, benefits and potential risks of the alternatives proposed.
Passing from a doctor-centered to a patient-centered model of health has led in the last decades to an increase in the interest devoted to informed consent and how to ensure that decisions are indeed knowledgeable. The roles of presentation format and numeracy in enabling patients to understand statistical information are also discussed. We conclude that previous perceptions of the severity of a health condition modulate the use of probabilistic information for decision-making. Neither numeracy nor presentation format affected recommendation but both affected difficulty, worrying and probability rates. A model taking into consideration severity and worry rates best explained decisions in the cancer scenario in contrast, in the hypertension scenario the model that best explained the recommendations comprised both the posterior probability estimate and the severity rate. Importantly, regression analyses showed that the recommendations in the two health scenarios depended on different variables. The scenarios differed significantly in perceived severity and worry, with the cancer scenario obtaining higher scores. Participants’ numeracy was also assessed. All the rates used the same 1 (little)-8 (a great deal) scale. Finally, they rated the extent to which they would recommend the preventive measures. They had also to rate the prior probability of suffering from this medical condition, and the posterior probability of it, provided a positive mammogram or a rich-sodium diet. After reading the health scenario, participants had to rate its difficulty, and how worrisome it was. Before seeing the data, participants rated the severity of the disease and the inconvenience of the preventive measure. They also received information regarding a preventive measure (mammogram/low-sodium diet) and the likelihood of a positive mammogram or a rich-sodium diet either when suffering or not suffering from the disease. A sample of university students were presented with two health scenarios containing statistical information on the prevalence of breast cancer and hypertension either through icon arrays ( N = 71) or natural frequencies ( N = 72). This study aimed to assess the extent to which the influence of these factors might vary between different medical conditions. Furthermore, the comprehension of probabilities is commonly affected by the presentation format, and by numeracy. Nevertheless, previous beliefs and emotional reactions also have a role in decision-making. Ideally, decisions regarding one’s health should be made after assessing the objective probabilities of relevant outcomes. 2Institute of Neurosciences, University of Barcelona, Barcelona, Spain.1Section of Cognitive Processes, Department of Cognition, Development and Educational Psychology, Faculty of Psychology, University of Barcelona, Barcelona, Spain.
Àngels Colomé 1,2*, Javier Rodríguez-Ferreiro 1,2 and Elisabet Tubau 1,2