Crowdsourcing is increasingly used to engage people to contribute data for a variety of purposes to support decision-making and analysis. A common assumption in many crowdsourcing projects is that experience leads to better contributions. In this research, we demonstrate limits of this assumption. We argue that greater experience in contributing to a crowdsourcing project can lead to a narrowing in the kind of data a contributor provides, causing a decrease in the diversity of data provided. We test this proposition using data from two sources-comments submitted with contributions in a citizen science crowdsourcing project, and three years of online product reviews. Our analysis of comments provided by contributors shows that the length of comments decreases as the number of contributions increases. Also, we find that the number of attributes reported by contributors decreases as they gain experience. These finding support our prediction, suggesting that the diversity of data provided by contributors declines over time.
Building trustworthy systems where data, people, and purpose align