Deb Barma, S.Mahesha, A.2026-02-082023Hydrological Sciences Journal, 2023, Vol.68, 5, p.731 -7322626667https://doi.org/10.1080/02626667.2023.2185524https://idr.nitk.ac.in/handle/123456789/34276The research paper by Akçay et al. applied innovative polygon trend analysis (IPTA) to derive trend length/volume and trend slope between two consecutive months for rainfall/streamflow in the eastern Black Sea basin, Turkey. Although the trend length/volume equation is correct, the trend slope equation is fundamentally incorrect. A brief discussion is presented to apprise the research community of the correct trend slope equation. © 2023 IAHS.innovative polygon trend analysistrend analysistrend slope