Good Question! The Effect of Positive Feedback on Contributions to Online Public Goods
This work addresses the decline in participation in online Q&A communities by demonstrating that positive feedback can increase both asking and answering contributions, with implications for platform design.
A field experiment on Stack Overflow (N=22,856) found that receiving an anonymous upvote increased users' likelihood of asking another question by 6.3% and answering someone else's question by 12.9% within four weeks, with the effect on answering persisting for twelve weeks. A second upvote had no additional effect, and algorithmic amplification (visibility) was crucial for the answering effect but not for asking.
Online platforms where volunteers answer each other's questions are important sources of knowledge, yet participation is declining. We ran a pre-registered experiment on Stack Overflow, one of the largest Q&A communities for software development (N = 22,856), randomly assigning newly posted questions to receive an anonymous upvote. Within four weeks, treated users were 6.3% more likely to ask another question and 12.9% more likely to answer someone else's question. A second upvote produced no additional effect. The effect on answering was larger, more persistent, and still significant at twelve weeks. Next, we examine how much of these effects are due to algorithmic amplification, since upvotes also raise a question's rank and visibility. Algorithmic amplification is not important for the effect on asking additional questions, but it matters a lot for the effect on answering other questions. The increase in visibility increases the probability that another user provides an answer, and that experience appears to shift the poster toward broader community participation.