ABA glossary
Latency
Also called response latency
Definition
The time from the onset of a stimulus, such as an instruction, to the start of the response.
In plain words
Latency measures how quickly someone starts responding after a cue. It is useful when the problem is delay: a learner who follows instructions but takes two minutes to start, or a student who takes a long time to begin work after the teacher says "Start." It can also show improvement when a goal is to wait, such as a longer delay before grabbing food. The clock starts when the cue ends or is presented, as the program defines, and stops when the response begins, not when it ends.
Example from a session
The RBT says, "Clean up, please," and starts a stopwatch. Nico picks up the first block 12 seconds later, and she stops the watch: a latency of 12 seconds. Across five instructions she records 12, 30, 8, 20, and 10 seconds, a mean latency of 16 seconds. The goal in Nico's plan is a latency of 10 seconds or less.
For BCBA candidates and supervisors
Latency is often the target in compliance and instruction-following programs, and it is closely tied to prompt delay procedures, which deliberately set the time between the instruction and the prompt. In functional assessment, latency to the first response is also the basis of latency-based functional analyses, which reduce the number of times dangerous behavior must occur. Analysts specify the exact start and stop points in the definition, because small differences (end of instruction versus start of instruction) change the values.
Often confused with interresponse time, duration
Latency starts at a stimulus (an instruction or cue) and ends when the response begins. IRT starts when one response ends and stops when the next one of the same behavior begins. Duration is how long the response itself lasts. If the stem names an instruction or cue as the start point, the answer is latency.
Exam tip
Find the starting event. An instruction, question, or signal means latency. The end of a previous response of the same behavior means IRT. The beginning of the behavior means duration.
Can you spot latency in a scenario?
Practice RBT A.1 with exam-style questions and instant feedback.