Measuring Interresponse Time (IRT)

Interresponse Time (IRT)

  • IRT is the measure of time that elapses between two consecutive instances of the same behavior.

Definition

  • IRT is the time between two repeated instances of the same behavior.
  • Crucially, IRT measurement focuses on the time between occurrences of an identical behavior.
  • IRT is related to the rate of responding.

Data Collection

  • Tools:
    • Stopwatch
    • Timer apps (for electronic data collection)
  • Process: Measure the time from the end of one behavior to the beginning of the next instance of the same behavior. For example, from the end of one screaming instance, to the beginning of the next screaming instance.

IRT and Rate of Responding

  • Inverse relationship:
    • Lower IRT = Higher rate of responding (behaviors occur more quickly).
    • Higher IRT = Lower rate of responding (more time elapses between behaviors).
    • These are essentially the inverse of each other.

Graphing IRT Data

  • Calculation:
    • Average interresponse time.
    • Range (lowest IRT to highest IRT).

Practical Application of IRT

  • Used to measure the time between instances of the same behavior.
  • Helps understand how quickly behaviors occur in succession.

Usage

  • Increase the time between maladaptive behaviors (to decrease their frequency).
  • Decrease the time between appropriate behaviors (to increase their frequency).

Examples

  • Example 1: Imani
    • Scenario: Swiping the table.
    • Observation: IRT increased from 5 minutes to 10 minutes.
    • Interpretation: Imani is tolerating work for twice as long.
  • Example 2: Charlie
    • Scenario: Screaming in the bathroom (potentially due to fear of an extractor fan).
    • Observation: IRT of 2 seconds between screams.
    • Interpretation: Screaming is consistent throughout the bathroom visit.
  • Example 3: Christian
    • Scenario: Bites of food.
    • Observation: IRT increased from 5 seconds to 30 seconds.
    • Interpretation: Intervention likely implemented to address eating too quickly; now he is taking time to chew and swallow.