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Normalized Reaction Time Active Task Export Format

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The Normalized Reaction Time Active Task is based on the ResearchKit Reaction Time test. Instead of shaking the device in response to the stimulus, however, the participant simply lifts their finger and taps the stimulus when it appears.

When your project uses the CSV export format for Survey Results, data for Active Tasks is exported in the file SurveyNormalizedReactionTimeResults.csv. When your project uses the JSON export format, Active Task data is included in the file SurveyResults.json.

For a typical survey using this task, you'll expect to see:

  • One survey result each time the participant completes the survey.
  • One step result representing the Active Task.
  • One NRT result for each attempt in that step. The individual prompts and responses are captured within that result.

There are several timestamps within the Normalized Reaction Time task, illustrated by the diagram below.

NRT-Sequence.png

Table of Contents

Data Fields

Field Description
SurveyNormalizedReactionTimeResultKey

A unique, auto-generated observation ID for a single reaction time attempt.
SurveyStepResultKey A unique, auto-generated key for this step result. Can be used to cross reference with other survey results.
SurveyResultKey The key for the survey result which this step result is contained in. Can be used to cross reference with other survey results.
ParticipantIdentifier The identifier of the participant this task was for. Can be used to cross reference with Participants.
ReactionDate

A device timestamp representing when the stimulus is tapped.

Note: This value is zero if the stimulus is not tapped before the timeout.
StimulusStartDate

A device timestamp representing when the stimulus appears.

Note: This value is zero if the finger is lifted before the stimulus appears.
TimerStartDate

A device timestamp representing when the participant lifts their finger off the 'hold' button after the stimulus appears.

Note: This value is zero if the finger is lifted before the stimulus appears.
TimerEndDate A device timestamp representing when the stimulus is tapped or the timeout is reached.
CurrentInterval A randomized delay (in seconds) from when the test starts to when the stimulus appears.
StartDate The timestamp for when the participant started the test, in ISO 8601 format. Includes timezone offset information.
EndDate The timestamp for when the participant completed the test, in ISO 8601 format. Includes timezone offset information.

Sample CSV Export

SurveyNormalizedReactionTimeResultKey,SurveyStepResultKey,SurveyResultKey,ParticipantIdentifier,ReactionDate,StimulusStartDate,TimerStartDate,TimerEndDate,CurrentInterval,StartDate,EndDate
1111-22222-33333,aaaa-bbbbb-ccccc,dddd-eeee-ffff,TestID54,296514.00222925004,296513.57842845836,296513.83621108334,296514.002296875,2,2021-01-13T11:15:17-05:00,2021-01-13T11:15:17-05:00
4444-55555-66666,aaaa-bbbbb-ccccc,dddd-eeee-ffff,TestID54,0,0,0,296546.42473716667,6,2021-01-13T11:15:49-05:00,2021-01-13T11:15:49-05:00

Sample JSON Export

Note that since the JSON export is included in the SurveyResults.json file, some of the reference keys either do not apply, or are part of the overall survey step data.

{
  "ReactionDate": 368686.43705948605,
  "StimulusStartDate": 368685.414478047,
  "TimerEndDate": 368686.437065418,
  "TimerStartDate": 368685.762244465,
  "Type": "NormalizedReactionTimeResult",
  "EndDate": "2020-01-03T15:29:13-0600",
  "StartDate": "2020-01-03T15:29:13-0600",
  "Identifier": "REACTION_TIME_TEST",
  "CurrentInterval": 4
},
{
  "ReactionDate": 0,
  "StimulusStartDate": 368695.362009235,
  "TimerEndDate": 368698.362137118,
  "TimerStartDate": 0,
  "Type": "NormalizedReactionTimeResult",
  "EndDate": "2020-01-03T15:29:25-0600",
  "StartDate": "2020-01-03T15:29:25-0600",
  "Identifier": "REACTION_TIME_TEST",
  "CurrentInterval": 2
}

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