Defaults are one of applied behavioral science’s biggest success stories. Despite, or perhaps because of, the widespread use and success of defaults, a few important questions have remained in the background: How have defaults been implemented? Does it matter how they are implemented? This was the aim of a recent meta-analysis of all prior default studies conductd by the Center for Decision Sciences, which we recently published in Behavioural Public Policy (authors Jon Jachimowicz, Shannon Duncan, Elke Weber and Eric Johnson).
In total, we found 58 default studies with a total sample size of 73,675 participants. The studies came from a wide variety of contexts, topics, fields, and countries. One thing became apparent in our analysis: on average, defaults are a strong choice architecture tool, shifting decisions by 0.63 to 0.68 standard deviations. What this means is that in decisions where there are two possible options, the option that is preselected is on average chosen 27 percent more often than the option that is not preselected.
On the other hand, there were also substantial differences in the effectiveness of defaults. In some studies, a default was far more effective than in other studies; and in others yet, defaults did not alter participants’ decisions. This is an important caveat, which highlights that choice architects should not blindly apply defaults to all situations, but instead be more careful in when and how they implement defaults. We find that studies that were designed to trigger endorsement (defaults that are seen as conveying what the choice architect thinks the decision maker should do) or endowment (defaults that are seen as reflecting the status quo) were more likely to be effective. In addition, we find that defaults in consumer domains tend to be more effective, and that defaults in pro-environmental domains (such as green energy defaults) tend to be less effective.What this highlights is that the intensity and the distribution of decision makers’ underlying preferences—what it is that they care about and want—plays an important role in how effective defaults are.
When introducing defaults into complex real-world environments, choice architects thus need to be mindful that defaults are not the same by default.