Participants
The survey was conducted from January 21 to February 28, 2021. We emailed 179 contacts at 129 universities up to three times each. Fifty-two participants agreed to participate and forwarded our invitation to their students. Sixteen participants declined participation, and 111 were unresponsive after three attempts. Further, 3200 persons opened the link to the survey, and 923 accessed the link from social media. A total of 861 confirmed that they were PhD students and consented to participate. Overall, 630 participants were randomized to assess the impact of the exposure to the postdoctoral researcher (n = 315) and the supervisor (n = 315). Twenty-eight participants did not read the second vignette and were, consequently, excluded from the analysis (15 in the first trial and 13 in the second trial). Participants’ flow diagram is presented in Fig. Participants’ flow diagram.