Participant ID saved in name GZ-file not in name csv file

In an online experiment participants are redirected from qualtrics to pavlovia.

The gz-files on pavlovia save the participant ID from qualtrics correctly in the beginning of the name of the file.
However, this is not the case for the csv file. In the name of the csv file the participant ID is not saved.

Does anyone know how to solve this?

What URL are you using in Qualtrics? What variables are in your expInfo dialogue box?

I’m using the following URL in qualtrics:


In de expInfo dialogue box are:

  • participant
  • session

Both participant and session are recorded within the csv-files but not in the title of the csv files. So no important data are lost. Both are part of the title of the GZ-files.


I am also having this problem. The participant ID appears in the name of the gz files but not in the name of the csv files.

Is there a fix for this?

Just checking - if the participant ID is not at the start of the csv filename, will this potentially create an issue if two participants submit data at the same time? E.g. the csv files for those participants will have the same name?

Hi @7x8p6r,

I’ve encountered this bug in all 2022.x.x that I have tested (see Possible Bug: 2022.1.1 - 2022.1.3 URL Parameter not included in filename) and it does appear that there is a slight risk of data loss if two participants run the experiment simultaneously (one participant might overwrite the other). The default timestamp includes milliseconds, so the risk of this is quite low.

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Hi @Eline_Belmans & @7x8p6r,

You might be able to add a Javascript-only code component as a workaround for this issue. In the Before Experiment section of the code component you can add:


and this seems to force the URL parameters to be read before the participant file is created. I briefly tested this in a minimal example in Version 2022.2.4, but have not tried it in a full experiment yet.

Credit to @young1 for first proposing the workaround.