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Randomisation in Gorilla

  • Overview
  • Randomisation Options

Overview


This walkthrough introduces you to the various randomisation options within Gorilla. We know that the amount of different options can sometimes be confusing, so we have collated the different courses of action a user can make.

Randomisation Options


This table presents the different randomisation options Gorilla offers, and explains in what circumstances you should use which.

Type of randomisation Useful for Use Case Location
Trial order Within subject If you want to present a list of trials in a random (shuffled) order, use the randomise_trials column in the spreadsheet. Task Builder Spreadsheet Column
Block order Within subject If you have two (or more) blocks, you may want participants to be shown them in a different order. This can be achieved using the randomise_blocks column in the spreadsheet. Task Builder Spreadsheet Column
Stimuli set Between Subject If you want to present two different stimuli sets to participants, for instance an A and B set, then upload two different spreadsheets to the task. This can be useful for creating a pre-test and a post-test which are otherwise identical. You’d upload all the stimuli to the stimuli tab as normal. Task Builder Spreadsheet
Subset of stimuli Between Subject If you want to randomly select a subset of stimuli to be shown to participants, this script demonstrates creating a counterbalanced subset of trials based on multiple conditions, and can be adjusted to fit the conditions you want. Task Builder Scripting (first link)
Task Order Within Subject If you want to randomise the order of Task and Questionnaire Nodes within your experiment tree, use the Order Node. Experiment Tree Order Node
Experiment Group Between Subject If you want to distribute participants at random between 2 (or more) different paths through your experiment tree, use the Randomiser node. Experiment Tree Randomiser Node
Experiment Group Between Subject If you want to assign different stimuli sets to different participants, the counterbalance node can be used in conjuction with the source type spreadsheet manipulations. This is especially helpful if you have more than 4 stimuli sets, as the same effect can be achieved using many randomiser nodes, but the more stimuli sets, the more randomiser nodes you would have to use - which is where the helpfulness of the counterbalance node enters. Experiment Tree Counterbalance Node