Graphical summary of the major findings observed in the 22 studies under consideration. (a) Number of studies by radiofrequency electromagnetic field (RF‐EMF) effect occurrence (yes/no) and direction of RF‐EMF effect. (b) Number of studies reporting an RF‐EMF effect by frequency band and direction of RF‐EMF effect in relation to the number of studies that investigated the respective frequency band. Studies: 1. Röschke and Mann [1997], 2. Hietanen et al. [2000], 3. Croft et al. [2002], 4. D'Costa et al. [2003], 5. Curcio et al. [2005], 6. Perentos et al. [2007], 7. Regel et al. [2007], 8. Croft et al. [2008], 9. Hinrikus et al. [2008a], 10. Hinrikus et al. [2008b], 11. Kleinlogel et al. [2008], 12. Croft et al. [2010], 13. Hinrikus et al. [2011], 14. Loughran et al. [2013], 15. Perentos et al. [2013], 16. Suhhova et al. [2013], 17. Trunk et al. [2013], 18. Ghosn et al. [2015], 19. Curcio et al. [2015], 20. Roggeveen et al. [2015], 21. Zentai et al. [2015], 22. Yang et al. [2017].