A proposal to improve the calculation of the disruption index

Wu et al. (2019) proposed the disruption index (DI1) as a bibliometric indicator that measures disruptive and consolidating research. Leibel and Bornmann (2024) recently published a literature overview on the disruption index research in Scientometrics. In this letter to the editor, we point out that the method of calculating the DI1 score of a focal paper contains a logical impact measurement error that leads to a meaningful reduction of the score. We explain why this is problematic and propose a correction of the formula.