Based on Research By Ajay Kalra, Shibo Li and Wei Zhang

How Does Negative Information About A Drug Influence A Physician’s Decision To Prescribe It?

  • People update their beliefs based on various information sources, but the information they receive is often biased and, on the whole, contradictory.
  • When new, negative information is not clear cut, people with high levels of experience, expertise and self-efficacy are less affected, because these traits improve their ability to discern the nature and quality of biased information.
  • Firms could forfeit revenue when they don’t understand how different types of customers respond to contradictory information.

Nowadays, we often see headlines that make us question the quality of products that impact our health. One headline might say, “Helmet use reduces brain injuries.” Another might trumpet, “Helmet use and fatalities are correlated positively.” After reading such contradictory reports, helmet-wearing bikers must decide whether to continue using helmets. Sadly, physicians often are in the same boat. They must decide whether to continue prescribing a medication after receiving contradictory information about its quality. Consider Avandia – a leading diabetes drug. At the same time that the New England Journal of Medicine published a study that linked the drug with increased cardiovascular risk, it published an editorial that criticized the study’s research method. To boot, information published by others (e.g. the FDA) argued both for and against continued use of the drug.

Under circumstances where new negative information about a drug is not clear cut, how might a physician’s belief about the quality of the drug and, ultimately, future prescriptions be influenced? To help answer this question, Ajay Kalra, Herbert S. Autrey Professor of Marketing at Rice Business, and two co-researchers conducted a study that focused on the fallout from Avandia’s negative news event. They tested an empirical model where physicians use multiple sources of information (e.g. news, pharmaceutical representatives, patients) to learn about and then update their beliefs regarding a drug product.

A guiding assumption of the research model was that sources of information that physicians confront is often biased and contradictory. Nowadays, reporters don’t just give facts, they render opinions. And the point of so-called detailing by pharmaceutical sales reps is to favorably influence – er, educate –  physicians regarding the quality of their products. Couple this with free samples that reps often extend to physicians, and it’s clear why the assumption of biased, contradictory information often rings true.

Kalra and his team obtained data collected from January 2006 to October 2007 – before and after the Avandia news event on May 21, 2007. The data included information about 1,500 physicians, including specialists as well as hospital-based and office-based primary care physicians (PCPs), their prescription choices over time and how they were targeted by the marketing efforts of sales reps from various drugmakers. The researchers also collected print coverage associated with the negative news event, including articles published in the Wall Street Journal and on the websites of major organizations such as the FDA. They labeled each article as either negative or positive, and among the views espoused in 112 articles gathered, 65 were negatively biased and 47 were positively biased.

Findings from the analysis were clear: Different types of physicians react differently to new, contradictory information. Specifically, specialists’ prescription decisions are less influenced by sales rep activities (i.e. detailing and sampling) than are the decisions made by office-based PCPs. Similarly, decisions of hospital-based PCPs are less influenced by sales rep activities than are the decisions made by office-based PCPs.

Kalra and his team speculate that physicians react differently to new negative information as a result of different levels of experience, expertise and self-efficacy (self-confidence, particularly in adverse situations) associated with their practice area. For example, office-based PCPs are generalists who have less expertise and access to peer-interaction than do specialists and hospital-based PCPs. Also, specialists have greater self-efficacy, which explains why they react differently when compared to all PCPs.

In short, high levels of experience, expertise and/or self-efficacy improve a physician’s ability to learn by discerning the nature and quality of biased information. For example, regarding learning about product effectiveness, the researchers found that office-based PCPs’ beliefs are more susceptible to external influences (e.g. patient feedback, detailing) than the beliefs of specialists and hospital-based PCPs. Likewise, regarding learning about product safety, office-based PCPs rely on various sources of information to update their beliefs, including positive news reports, negative news reports, detailing and patient feedback. Specialists and hospital-based PCPs, on the other hand, rely on far fewer sources.

But physicians aren’t the only ones who respond to new negative information. Drugmakers also respond, but not always in the most effective way. For example, after the negative news event, Avandia’s management team reduced detailing for office-based PCPs, but maintained it for specialists and increased it for hospital-based PCPs. However, office-based PCPs are more influenced by new, negative information because they have less disease-specific experience and are more risk averse than specialists or hospital-based PCPs. So after a negative news event,  drugmakers actually should increase their detailing efforts toward office-based PCPs in order to counter their potentially damaging response. Indeed, data used in this study showed that office-based PCPs switched from prescribing Avandia to prescribing metformin, a long-standing competitive product, after Avandia’s negative news event. Moreover, the researchers found that responding appropriately to different types of physicians could boost prescriptions by as much as 149 percent after a drug suffers a negative news event.

What does all of this mean for patients who trust their physicians to make the right prescription decisions on their behalf? Well, the next time new, negative information emerges about a prescription medication that a patient takes, he or she should remember that the physician’s response to such information often depends on the type of physician they are: specialist or generalist?

Ajay Kalra is a marketing professor at Jones Graduate School of Business at Rice University.

To learn more, please see: Kalra, A., Li, S., & Zhang, W. (2011). Understanding responses to contradictory information about products. Marketing Science, 30(6), 1098-1114.