P. Stauning: Comment on “Troshichev et al. 2020: The PC index variations during 23/24 solar cycles: relation to solar wind parameters and magnetic disturbances.”: Invalid data base. Abstract. The contribution from O.A. Troshichev, S. Dolgacheva, N.A. Stepanov, and D.A. Sormakov: “The PC index variations during 23/24 solar cycles: relation to solar wind parameters and magnetic disturbances”, https://doi.org/10.1029/2020JA028491 , is to a large extent based on data made available at the web portal http://geophys.aari.ru/PCspaceweather. However, an examination of the data presented there has disclosed what appears to be serious errors in the calculated values of polar cap (PC) index values, amplitude span of the quiet day curves (QDC) used for the reference levels, and values of the solar wind merging (or geoeffective) electric field (E KL) used for calibration of polar magnetic data to form PC indices. Parts of the essential data files are reproduced in the Appendix here. Some of the discrepancies reported in the present commentary affect directly the illustrations presented in their contribution while other possible errors may not be apparent since the use of relative values in their presentation makes assessments difficult.