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Looking for the ROLEG V2 DSL? Head over to the Archive.


We refer to the .zip archive that is uploaded to the web application as the experiment package. This section gives an overview of the things that should be included in the experiment package. Two types of files can be included in the package, DSL files and resource files. DSL files contain the scripts that define the structure of the experiment. In ROLEG two kinds of DSL files exist: the Experiment Definition (.roleg) file and the Include (.rolinc) file. Resource files, such as images, sounds or videos can be used to create non-textual stimuli. Below, the different files are described in more detail.

Experiment Definition file (.roleg)
A plain text file that defines the structure and content of the experiment using the ROLEG DSL. This file determines the type of experiment and what the participants will see and hear (both through text in the DSL and by referencing resource files). Only 1 .roleg file should be included in the experiment package, although multiple (subsequent) experiments can be defined in a single .roleg file. See experiment for more detail.
Include file (.rolinc)
A plain text file that defines a smaller part of an experiment using the ROLEG DSL. In certain cases, it is useful to move part of a .roleg file into a separate .rolinc file. The code in the .rolinc file will still be interpreted if the .rolinc file is referenced in the .roleg file. This can be done to create a less cluttered .roleg structure or to vary the stimuli presented to the participants. See Include files section for more detail.
Sound files (.wav/.mp3)
ROLEG currently supports playback of both .wav and .mp3 files. Generally, .wav files have a higher audio quality but are much larger than .mp3 files. As such, if you have very many or long audio fragments, you may need to use .mp3 files to stay under the upload limit of the ROLEG website. Note that the ROLEG server will convert .wav files to .mp3 files before playing them to your participants. If audio quality (especially at very high frequencies) is very important in your study, you may want to test the sound output.
Images (.jpg/.gif/.png) and Videos (.mp4)
If you want to show images or videos to your participants, you will have to take image/video and screen size into account. ROLEG does not automatically scale images/videos to fit the screens of your participants. As a result, parts of the image/video may be cut off if it is too big. See the table at the bottom of this page for an overview of recommended sizes. Note that videos/images have to be smaller when the experiments show a field for text input in addition to the image or video. Most modern monitors have a resolution of at least 1280x800, but if it is critical that the entire image or video is visible, use the sizes listed next to ‘Lower than 1280x800’. In case you know that the participants will have a screen size larger than those listed above, you should test your experiment to find the maximum size for your image and video stimuli.

Once you have created all of your DSL and resource files, the experiment package (.zip) is created as follows:

  • Windows: Select all relevant files and right click → Send to → Compressed (zipped) folder
  • macOS: Select all relevant files and right click → Compress number of files

The .zip archive should contain the necessary files in its top level, that is, without any subdirectories. Therefore, make sure you compress your experiment files directly, instead of the folder containing those files.

The resulting .zip file can be uploaded to the ROLEG website (see Upload Experiment).


ROLEG maintains an upload limit of 150 MB on the compressed experiment package. If you find you reach this limit, try to reduce the resolution of included media to stay within this limit, such as compressing 1080p videos to 720p or convert your .wav files to .mp3 files on your computer before uploading.

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