Communicating probabilistic information to cancer patients: Is there ‘noise’ on the line?

• Published in: Social science & medicine (1982) Vol. 32; no. 6; pp. 725 - 731
• Main Authors: Sutherland, H.J., Lockwood, G.A., Tritchler, D.L., Sem, F., Brooks, L., Till, J.E.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1991; Elsevier; Pergamon Press Inc
• Series: Social Science & Medicine
• Subjects: Aged; Aged, 80 and over; Analysis of Variance; Biological and medical sciences; Cancer; Communication; Female; Humans; Informed Consent; Interpersonal communication; Interpretation; Male; medical ethics; medical ethics oncology subjective probability informed consent; Medical Oncology - methods; Medical sciences; Middle Aged; oncology; Outcomes; Patient Participation; Probability; Psychology; Public health. Hygiene-occupational medicine; Reproducibility of Results; Social research; subjective probability; Surveys and Questionnaires; Terminology as Topic; Treatment; informed consent; medical ethics; oncology; subjective probability; Human; Ethics; Questionnaire; Physician patient relation; Biomedical information; Informed consent; Subjective probability; Public health
• ISSN: 0277-9536; 1873-5347
• DOI: 10.1016/0277-9536(91)90152-3

The objective was to examine the way that cancer patients translate verbal descriptors of probability into numerical estimates. A list of words commonly used on consent forms to describe the likelihood for benefits or risks of therapies was provided to 100 cancer patients. Two formats, paper/pencil or computer, were used to provide the list of words. Two methods, magnitude estimation and linear analogue scaling, were used to obtain probability estimates for each word. In addition, two scenarios were developed to study ‘context effects’ on numerical interpretations of verbal descriptions of probability. All patients provided numerical values for the words on two occasions, separated by one week, and two interviewers collected the data. Regardless of method or format, each word elicited widely variable numerical interpretations. An ANOVA model, including patient, word, interviewer, time, method and format, indicated that patient and interviewer produced the major effects on probability estimates. Agreement between methods and across time was good. Paper/pencil and computer formats yielded similar results. Context effects did not appear to influence the numerical probabilities elicited by the 2 scenarios. It was concluded that, within this group of patients, there was no consensus about numerical meaning of a given word, and that interviewers can systematically influence numerical interpretations. There appears to be a great deal of ‘noise’ in this particular line of communication between patients and health professionals.