Does open access citation advantage depend on paper topics?

Research topics vary in their citation potential. In a metric-wise scientific milieu, it would be probable that authors tend to select citation-attractive topics especially when choosing open access (OA) outlets that are more likely to attract citations. Applying a matched-pairs study design, this research aims to examine the role of research topics in the citation advantage of OA papers. Using a comparative citation analysis method, it investigates a sample of papers published in 47 Elsevier article processing charges (APC)-funded journals in different access models including non-open access (NOA), APC, Green and mixed Green-APC. The contents of the papers are analysed using natural language processing techniques at the title and abstract level and served as a basis to match the NOA papers to their peers in the OA models. The publication years and journals are controlled for in order to avoid their impacts on the citation numbers. According to the results, the OA citation advantage that is observed in the whole sample still holds even for the highly similar OA and NOA papers. This implies that the OA citation surplus is not an artefact of the OA and NOA papers' differences in their topics and, therefore, in their citation potential. This leads to the conclusion that OA authors' self-selectivity, if it exists at all, is not responsible for the OA citation advantage, at least as far as selection of topics with probably higher citation potentials is concerned.