Vignette-based Experiment Research Articles

Do Physicians Attend to Base Rates? Prevalence Data and Statistical Discrimination in the Diagnosis of Coronary Heart Disease

To examine whether physicians attend to gender prevalence data in diagnostic decision making for coronary heart disease (CHD) and to test the hypothesis that previously reported gender differences in CHD diagnostic certainty are due to discrimination arising from reliance on prevalence data ("statistical discrimination"). A vignette-based experiment of 256 randomly sampled primary care physicians conducted from 2006 to 2007. Factorial experiment. Physicians observed patient presentations of cardinal CHD symptoms, standardized across design factors (gender, race, age, socioeconomic status). Structured interview. Most physicians perceived the U.S. population CHD prevalence as higher in men (48.4 percent) or similar by gender (44.9 percent). For the observed patient, 52 percent did not change their CHD diagnostic certainty based on patient gender. Forty-eight percent of physicians were inconsistent in their population-level and individual-level CHD assessments. Physicians' assessments of CHD prevalence did not attenuate the observed gender effect in diagnostic certainty for the individual patient. Given an adequate presentation of CHD symptoms, physicians may deviate from their prevalence data during diagnostic decision making. Physicians' priors on CHD prevalence did not explain the gender effect in CHD certainty. Future research should examine personal stereotypes as an explanation for gender differences.

What happens along the diagnostic pathway to CHD treatment? Qualitative results concerning cognitive processes

Extensive research on health disparities documents persistent differential diagnosis and treatment of many conditions according to patient characteristics, physician attributes, and healthcare systems. Less is known about how physicians arrive at their decisions. We use qualitative data from a vignette-based factorial experiment to examine how physicians reason through and account for their clinical decisions, and how variations arise despite the presentation of identical symptoms of coronary heart disease (CHD). We find that physicians show evidence of cognitive biases but also actively interpret social characteristics they deem relevant to medical treatment. In an uncertain clinical context, these diagnostic pathways expose key junctures wherein physicians are detoured to alternative diagnoses, their certainty of CHD lowered, and scientific logic makes it difficult to return to a CHD diagnosis - thereby providing a fuller picture of why some cases are counted as CHD while others are not. These results have important implications insofar as diagnostic decisions like these contribute to the compilation of epidemiologic base rates, and are therefore used as part of Bayesian decision making to determine the probability of CHD in subsequent patients. This work resonates with social constructivist concerns regarding the ways disease categories are established and maintained, and potential sources of bias in official rates detected.