Opt-in

What is opt-in?

Opt-in is an arrangement in which a person must take an affirmative step to join, enroll, or select an option. Without that step, the default is nonparticipation. An opt-out arrangement reverses this starting point.

Evidence and limits

The starting point can affect participation. Madrian and Shea (2001) compared retirement-plan behavior around a company’s change from active enrollment to automatic enrollment and found a substantial participation difference. A broader meta-analysis of defaults found that the size of default effects varies across settings.

This does not mean opt-in is always worse or opt-out always better. Participation rates, informed choice, and the consequences of enrollment are different measures. A study of retirement enrollment does not establish the effect of a default in organ donation, data sharing, or another domain.