医療における行動経済学とナッジ

抄録

Behavioral economics have provided various insights to decision making problems for the last decades. In this article, I briefly introduce a few of the researches that are applied or applicable to healthcare and clinical decision making problems. In the last section, I also highlight the ideas of Nudge for behavior changes. The topics include the probability weighting and the S-shaped value function in Prospect Theory, the ambiguity aversion, and the cognitive biases such as framing effect, confirmation biases, and overconfidence.

The decision makings under uncertainty have been thoroughly researched and analyzed by formal models. At the same time, there have been many reported anomalies or "irrational behaviors" in the literature, which simply contract with those formal models. To incorporate the irrational behaviors, the researchers have also developed and modified the existing models. The Prospect Theory is definitely one of the most successful modifications. It is consist of two main components, the probability weighting function and the S-shaped value function. These functions combined together offer the broader framework that can explain several well-known anomalies, and they enable us to analyze the source of the irrationality in the clinical decision makings.

The psychology researches identify numerous forms of cognitive biases. We must be aware of those systematic tendencies of biases within our own decision makings, before we start debates over whether some decisions are rational or irrational, whether they are justifiable or not, and whether they are correct or wrong. Although it is still difficult for us to correct our unconscious biases at the site, it is important to understand the tendency of cognitive biases to prevent us from repeating any similar mistakes, if any, in the future. For this purpose, I select confirmation bias and overconfidence to write about.

Lastly, the concept of "nudge" is highlighted. A nudge is a behavioral science oriented method of guidance toward behavior changes. For instance, when an authority wants to make people do vaccinations, it can request or require them to do so, or subside for vaccinations. Instead, a simple letter that asks people to decide when to take the vaccination successfully worked. While requests, requirements and subsidies are active and explicit interventions, the nudge is rather passive and implicit and it is effective, too. There are varieties of nudges that are applicable to healthcare. I introduce a couple of examples to show the great potential of nudges in this field.