<p>This paper develops an organization design-oriented conceptual model of scientific knowledge production through citizen science virtual organizations. Citizen science is a form of organization design for collaborative scientific research involving scientists and volunteers, for which Internet-based modes of participation enable massive virtual collaboration by thousands of members of the public. The conceptual model provides an example of a theory development process and discusses its application to an exploratory study. The paper contributes a multi-level process model for organizing investigation into the impact of design on this form of scientific knowledge production.</p>