BCBA Measurement Glossary
Key terms and definitions for Measurement, Data Display & Interpretation.
Frequency
A count of the number of times a behavior occurs within an observation period.
Rate
The frequency of a behavior divided by the time during which it was observed, typically expressed as responses per minute or per hour.
Duration
The total amount of time a behavior occurs from onset to offset.
Latency
The elapsed time from the onset of a stimulus (e.g., an instruction) to the initiation of the response.
Interresponse Time (IRT)
The elapsed time between two consecutive responses.
Partial Interval Recording
A discontinuous measurement procedure in which the observer records whether the behavior occurred at any point during a specified time interval.
Whole Interval Recording
A discontinuous measurement procedure in which the observer records the behavior only if it occurred throughout the entire interval.
Momentary Time Sampling
A discontinuous measurement procedure in which the observer records whether the behavior is occurring at the exact moment the interval ends.
Interobserver Agreement (IOA)
The degree to which two or more independent observers report the same observed values after measuring the same events. Used to assess measurement reliability.
Reversal Design (ABAB)
A single-subject experimental design that demonstrates a functional relationship by alternating between baseline (A) and treatment (B) conditions.
Multiple Baseline Design
A single-subject design that demonstrates a functional relationship by introducing the independent variable sequentially across participants, settings, or behaviors.
Changing Criterion Design
A single-subject design that demonstrates control by showing that behavior changes systematically with each change in the criterion for reinforcement.
Multielement Design
A single-subject design that compares two or more conditions by rapidly alternating between them (also called alternating treatments design).
Visual Analysis
The systematic examination of graphed data to identify changes in level, trend, and variability within and across conditions.
Level
The value around which a series of data points converge, often described as the mean or median of data within a condition.
Trend
The direction and degree of change in data values over time within a condition (increasing, decreasing, or zero/flat).
Variability
The degree to which data points deviate from the overall trend within a condition.
Cumulative Record
A graph in which the y-axis shows the cumulative number of responses and the x-axis shows time. The slope indicates the response rate.