ABA glossary
Rate
Also called response rate
Definition
A count divided by the observation time, such as responses per minute or per hour. Rate makes sessions of different lengths comparable.
In plain words
Rate answers "how often per unit of time." It is calculated by dividing the number of responses by the time observed: 18 requests in 90 minutes is 0.2 per minute, or 12 per hour. Converting counts to rate lets the team compare a 30-minute session with a 2-hour session on the same graph. Rate is the natural measure for free-operant behavior, which can occur at any time without being limited by trials or prompts.
Example from a session
On Monday Jaylen calls out 12 times in a 30-minute group; on Tuesday he calls out 18 times in a 60-minute group. The count went up, but the RBT calculates rate: 12 ÷ 30 = 0.4 per minute on Monday and 18 ÷ 60 = 0.3 per minute on Tuesday. Calling out actually decreased. The RBT enters the rates on the graph as the plan specifies, not the raw counts.
For BCBA candidates and supervisors
Rate is a sensitive measure of change and the basis for celeration (change in rate over time) on the Standard Celeration Chart. Analysts avoid rate for restricted operants, where the teacher controls opportunities (as in discrete trials), because rate then reflects the pace of trial presentation rather than the learner's behavior; percentage or trials to criterion fits better. When rate is reported, the observation time should exclude periods when the behavior could not occur, such as breaks away from the setting.
Often confused with frequency, percentage
Count is a raw number; rate is count per unit of time. Percentage is a ratio of responses to opportunities (or of correct to total responses), not to time. Use rate when the observation time varies and the behavior can occur freely; use percentage when the number of opportunities varies, such as trials or steps.
Exam tip
For calculation items, divide the count by the time in the unit the question asks for, converting minutes to hours if needed. 24 responses in 2 hours is 12 per hour or 0.2 per minute. Watch for distractors that divide time by count.
Can you spot rate in a scenario?
Practice RBT A.1 with exam-style questions and instant feedback.