Citation bias in measuring knowledge flow: Evidence from the web of science at the discipline level

Knowledge flow between scientific disciplines has commonly been measured based on citation data. Previous studies using citing relationships have mostly considered direct citations but have paid little attention to indirect citations (IDC) to indicate how knowledge diffusion from one dis-cipline to another via one or more intermediaries. In this study, we measured knowledge flow between disciplines from two perspectives: direct citations (DC) and discipline potential energy (DPE), which is proposed to combine both direct and indirect citations. Data were collected from the Web of Science (WoS) database. Findings include: specialIntscript DPE overshadows previous measures by considering not only direct citations but also indirect citations between disciplines which was usually ignored in previous measures, and revealed that the knowledge contribution of some dis-ciplines had been underestimated by previous measures, such as Physics and Engineering. specialIntscript The proportion of IDC contribution is close to that of direct knowledge contribution when the discipline scale is removed, which suggests that it is essential to consider IDC to distinguish the knowledge relationship (net-outflow/inflow) between disciplines. specialIntscript Both measurements show that Biology & Biochemistry has always been the top discipline with the highest net outflow of knowledge, which is inconsistent with the history of science that Mathematics, Physics and Chem-istry would be the highest net outflow disciplines. The results show that even considering IDC does not fully reveal the knowledge contribution and academic influence of disciplines. This paper also analyzes the potential reasons for citation bias in revealing the contribution of disciplinary knowledge from a citation perspective. Therefore, caution should be taken in the use of citations as a primary measure of knowledge flow.