Overview
This lecture focused on the topic of measurement in Applied Behavior Analysis (ABA), highlighting its importance, key measurement procedures, and how to select appropriate methods for various behaviors.
Importance of Measurement in ABA
- Measurement provides objective evidence of behavior change.
- Defining and measuring target behaviors clarifies what is being addressed.
- Accurate measurement helps evaluate progress and intervention effectiveness.
Selecting Measurement Procedures
- Measurement Validity: Choose procedures that capture relevant behavior dimensions for change.
- Data Collector Feasibility: Ensure accuracy is possible given the collector’s responsibilities.
Types of Measurement
- Continuous Measurement: Captures all instances (requires constant observation; e.g., frequency, rate, duration, latency, IRT).
- Discontinuous Measurement: Estimates behavior via time intervals (reduces observer load, introduces measurement artifacts).
Continuous Measurement Procedures
- Frequency: Number of times a behavior occurs; best for behaviors with consistent durations per instance and fixed observation periods.
- Rate: Frequency per unit time; best for comparing behaviors across sessions of variable length.
- Duration: Total time a behavior occurs; used when behaviors vary in length.
- Latency: Time from stimulus to behavior onset.
- Interresponse Time (IRT): Time between the end of one response and the start of another.
Discontinuous Measurement & Artifacts
- Interval Recording (e.g., partial interval, momentary time sampling) uses time segments to estimate behavior.
- Measurement Artifact: Data misrepresentation caused by measurement method (e.g., partial interval overestimates behavior).
Dimensional Qualities of Measurement
- Repeatability: Behavior can be counted (frequency).
- Temporal Extent: Behavior has duration (duration).
- Temporal Locus: Behavior occurs at a specific time (latency, rate, IRT).
Application Examples
- Use frequency for counts within single, fixed sessions (e.g., "How many hot dogs did you eat at one event?").
- Use rate to compare across sessions with varied lengths (e.g., "How many aggressive acts per hour in ABA sessions?").
- Use duration for behaviors with variable episode lengths (e.g., screaming episodes lasting from seconds to 30 minutes).
Key Terms & Definitions
- Measurement Validity — Data reflects the dimension of behavior targeted for change.
- Measurement Artifact — Error in reported data caused by the measurement method, not by true behavior.
- Continuous Measurement — Captures all relevant behavior instances.
- Discontinuous Measurement — Estimates behavior using intervals or sampling.
- Frequency — Number of times a behavior occurs.
- Rate — Frequency expressed per unit of time.
- Duration — Total time behavior occurs.
- Latency — Time from stimulus to behavior start.
- IRT (Interresponse Time) — Time between behavioral responses.
- Repeatability — Behavior is countable.
- Temporal Extent — Duration of a behavior.
- Temporal Locus — Time point when behavior occurs.
Action Items / Next Steps
- Review dimensional qualities (repeatability, temporal extent, temporal locus).
- Practice identifying appropriate measurement methods for various behaviors.
- Prepare for part two of the measurement lecture next week.