Is Open Access a Cause or an Effect? | The Scholarly Kitchen
"A notable science journal implements a new author service: For $5,000, the publisher will make that article freely available (OA) to the world upon publication. A substantial number of authors purchase this service, either by choice or because they were required to do so by their funding agency, and the program is deemed a success. Several years later, the publisher is interested in knowing whether those articles made freely available performed any better than articles moving through the traditional publication route–in this case access by subscription. The publisher hires a consulting firm, gathers citation data at a particular point of time and makes a simple comparison between the OA group and the subscription group. The results show with remarkable clarity that the OA group significantly outperformed the subscription group. Does that mean that OA was the cause of the difference? Maybe. But before OA is considered to be a cause, the analyst needs to rule out other potential explanations for the effect. Authors elected to pay $5,000 for the OA service, and that choice alone may signal that there is something very different about the OA group compared to the subscription group. Specifically, the OA article group may:  Represent researchers with better access to research and publication funds than those in the subscription group  Represent research funded by an organization that mandates–and pays for–OA publication  Represent researchers located at institutions (or labs) that generate high-profile work, or  Represent research performed by high-profile researchers There are many attributes of papers that are hard to quantify, like novelty, relevance, and impact ..."