I’ve done some detailed analysis of @Tuongvan’s data files, since they are using my VESPR Study Portal which gives a some extra timestamps and I’ve worked on their experiment.
Participant 9 (who completed the task) launched at Fri Apr 30 2021 12:05:34 GMT+0000; reached the debrief at Fri Apr 30 2021 13:05:02 GMT+0000 (one hour later) and the timestamp is 9_Tetris_B_210128_2021-04-30_14h05.44.748.csv (10 seconds after the initial launch). The data was saved at 1:03pm (after 58 minutes).
Participant 17 launched at Tue May 04 2021 10:47:47 GMT+0000 and the timestamp is 17_Tetris_B_210128_2021-05-04_12h47.53.896.csv (6 seconds later). The data was saved at 11:07 (after 20 minutes).
Participant 19 launched from my site at Tue May 11 2021 14:17:17 GMT+0000 and their empty data file is named PARTICIPANT_Letris_210201_2021-05-11_16h17.21.761.csv, which is 4 seconds later accounting for time zones. The data was saved at 2:17pm (i.e. less than a minute).
Participant 20 (me trying to save some partial data) launched from my site at Tue May 11 2021 17:36:31 GMT+0000 and my data file is named 20_Tetris_B_210128_2021-05-11_18h40.24.362.csv which is nearly 4 minutes later, accounting for my time zone, which will probably be the time between reaching the expInfo dialogue box and pressing OK. The data was saved at 5:41 (after 1 minute).
Participant 21 launched at Tue May 11 2021 19:22:03 GMT+0000. There is no data file corresponding to this participant, which suggests to me that they either closed their browser without giving time for the data file to save or are currently in the experiment (it was less than an hour ago).
The data file for participant 19 therefore dates back to the initial setup of the experiment and suggests to me that they pressed escape or cancel on the expInfo dialogue box right at the start.
My conclusion is that if a participant presses Cancel or Escape at the dialogue box doesn’t cost a credit and an empty data file is saves without a participant number and using the psyexp file name instead of the Builder experiment name in the data file.