Self-selected or mandated, open access increases citation impact for higher quality research

Area of Science:

• Bibliometrics
• Scholarly Communication
• Open Science

Background:

• Articles made Open Access (OA) through self-archiving receive significantly more citations than non-OA articles.
• A potential self-selection bias, where authors preferentially archive higher-quality articles, has been proposed as an alternative explanation for this citation advantage.

Purpose of the Study:

• To differentiate between causal effects and self-selection bias in the Open Access citation advantage.
• To analyze the impact of mandatory versus self-selective self-archiving on citation rates.

Main Methods:

• Comparative analysis of 27,197 articles published between 2002-2006 across 1,984 journals.
• Logistic regression analysis to assess the OA Advantage independently of other citation correlates.

Main Results:

• The Open Access Advantage was equally high for both self-selective and mandatory self-archiving.
• The citation advantage of OA is independent of article age, journal impact factor, number of co-authors, references, pages, field, article type, or country.
• The OA Advantage is most pronounced for highly cited articles.

Conclusions:

• The Open Access Advantage is a real, independent, and causal effect, not solely due to author self-selection bias.
• The increased citation rate for OA articles stems from users selecting and citing more citable content, unhindered by access restrictions.
• Findings support the adoption of mandatory Open Access self-archiving policies by institutions and funders.