Do Open-Access articles really have a greater research impact?

Abstract

The study of citation behavior is complex and involves multiple confounding, and interacting variables. Methodologically, it is very difficult to distinguish whether Open Access is an explanatory cause of increased access, or whether it is merely an artifact of other causal explanations such as article duplication or self-promotion. Do Open-Access articles really have a greater research impact, as many suggest? Yes, but Open Access may not be the cause.