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Trial Data

In cognitive assessments, a typical way to record data is to store multiple trials of an assessment. Each trial has a similar data structure. m2c2kit has capabilities to make it easy to work with trial data:

  • The variable trialIndex keeps track of the trial number. This is 0-based, so the first trial is number 0.
  • The method addTrialData() adds data to the current trial.
  • The method trialComplete() marks the current trial as complete. This method also increments the trialIndex variable.

Each of the above are properties or methods on the m2c2kit Game object. Thus, you would access the trial index with game.trialIndex and mark the trial as complete with game.trialComplete(). The addTrialData() method takes arguments, which we explain below.

Adding trial data​

The addTrialData() method takes two arguments:

  • The variable name to which you are adding data. This is a string, and it must match a variable name defined in the schema.
  • The value to add to the variable. This can be any value that is valid for the variable type. For example, if the schema defined variable is a number, then the value must be a number.

For example, if your schema defined the variable response_time_duration_ms as a number, and the user took 529 milliseconds to respond, then you would add data to that variable with game.addTrialData("response_time_duration_ms", 529).1

If you try to add a value that does not match the schema, then m2c2kit will throw an error. Assuming that response_time_duration_ms was defined as a number, the below statements would throw an error:

  • game.addTrialData("response_time_duration_ms", false)
  • game.addTrialData("response_time_duration_ms", null)
  • game.addTrialData("response_time_duration_ms", "529")

Footnotes​

  1. This is a contrived example. It would be very unusual to provide an actual number, 529, in your code. In practice, the user's response time would be coming from another variable in your code, such as rt, and your code would be adding that to the schema with game.addTrialData("response_time_duration_ms", rt). ↩