Significance High attrition from educational programs is a major obstacle to social mobility and a persistent source of economic inefficiency. Over two-thirds of students entering a 2-y institution fail to earn a credential in the United States. In online courses, attrition rates are even higher. In two large field experiments, we tested the conditions under which a writing activity that facilitates goal commitment and goal-directed behavior reduces attrition in online courses. The activity raised completion rates by up to 78% for members of individualist cultures and primarily for those who contended with predictable and surmountable obstacles in the form of everyday obligations, but it was ineffective in collectivist cultures and for people contending with other types of obstacles.