An interval recording calculator converts interval data into percentages by dividing scored intervals by total intervals. This tool accepts 20 rows of ten 0/1 samples, then compares true duration, partial interval, whole interval, and momentary time sampling scores for RBT exam study.
Calculator Inputs#
The widget uses one timeline box so the scoring rules stay visible.
| Input | What to enter | Why it matters |
|---|---|---|
| Timeline rows | 20 rows, each with ten 0/1 samples | Each row is one modeled interval, and each character is one modeled second. |
| 0 samples | Use 0 when the behavior is absent during that second | Zeros keep the row from counting as a whole-interval row. |
| 1 samples | Use 1 when the behavior is present during that second | Ones drive the true-duration, partial-interval, whole-interval, and endpoint results. |
| Interval buttons | Cycle a row between absent, some, and whole examples | The buttons are practice shortcuts; the textarea remains the source data. |
Use rbt calculators when a question asks for a different tool, because interval recording, rate, cost, and recertification dates rely on different denominators. Choosing the denominator is the real exam skill before any calculator can help.
Scoring Assumptions#
The calculator follows the study rules below; real client data sheets follow the supervisor's written plan.
| Method | Score an interval when... | Common exam trap |
|---|---|---|
| True duration | Count every 1 across all 200 modeled seconds | Treating interval percentage as continuous duration. |
| Partial interval | The row contains at least one 1 | Treating the score as the number of responses. |
| Whole interval | The row contains no 0 samples | Scoring an interval yes after a brief occurrence. |
| Momentary time sampling | The final sample in the row is 1 | Watching the whole interval instead of checking the endpoint. |
The BACB Initial Competency Assessment Packet also lists discontinuous measurement with partial and whole interval and momentary time sampling as a measurement skill. The packet supports why these terms matter for technician competence, while the TCO states the exam task.
Worked Example#
The example below shows the independent calculation the widget should match.
A practice timeline has 20 equal rows. Seven rows contain 1111111111, seven rows contain 0001100000, and six rows contain 0000000000.
True duration: (7 x 10) + (7 x 2) = 84 seconds
84 / 200 seconds = 42%
Partial interval: 14 rows with at least one 1 / 20 rows = 70%
Whole interval: 7 rows with all 1 samples / 20 rows = 35%
Momentary time sampling: 7 rows ending in 1 / 20 rows = 35%
The partial-interval score is higher than true duration because a row with two present seconds still counts as a scored interval. The whole-interval score is lower than true duration because a row must stay present for every sample. The momentary score can fall on either side because it checks the endpoint sample, not the whole row.
For rate or percentage questions that are not interval based, use the aba rate calculator instead. That calculator is better when the stem gives responses per minute, mean duration, or another A.6 summary that does not depend on interval scoring.
Study Use#
The safest study sequence is rule first, numerator second, denominator third.
- Identify whether the scenario says any point, entire interval, or exact moment.
- Count only intervals that meet that rule.
- Divide scored intervals by total intervals.
- Convert the decimal to a percentage.
- Label the result as a scored-interval percentage, not direct frequency or true duration.
The rbt data collection and graphing study guide is the better review path when the problem is not arithmetic but deciding among continuous measurement, discontinuous measurement, permanent product, graphing, and reliability tasks. Use that guide before mixed Domain A practice.
The rbt recertification calculator belongs to a different workflow because BACB maintenance dates depend on the certification expiration shown in the account. Do not use interval data or generic transition dates to infer a person's recertification deadline.
Practice Items#
These original questions test the interval rule, the percentage calculation, and the data-quality risk without using BACB exam content.
1. During independent reading, a sheet says to mark yes only when Mateo keeps eyes on the page from the timer's start beep to its end beep. Which procedure is being used?
A Correct. Whole interval recording scores yes only when the behavior lasts for the entire interval.
B Partial interval recording would score yes after any occurrence during the interval.
C Momentary time sampling checks whether the behavior is occurring at a specific instant.
D Permanent-product recording measures a lasting result rather than live interval occurrence.
2. A practice sheet has 20 intervals, and 12 intervals are scored yes under the written interval rule. What percentage should the RBT enter?
A Thirty-two percent adds 20 and 12 instead of dividing 12 by 20.
B Forty percent uses the unscored intervals as if they were the numerator.
C Correct. Twelve divided by 20 equals 0.60, and 0.60 multiplied by 100 equals 60%.
D Twelve percent treats the scored count as a percent instead of dividing 12 by 20.
3. Jordan records interval data but forgets whether the plan required whole interval or momentary time sampling. What is the main risk?
A Graphing does not repair an unclear measurement procedure.
B Equal intervals do not turn discontinuous recording into an exact response count.
C A percentage summary cannot replace the missing rule used to produce the data.
D Correct. Unclear interval rules can make measurement unreliable because observers may score the same session differently.
FAQ
What is interval recording?
Interval recording is discontinuous measurement that divides an observation into intervals and scores whether the target behavior meets a specific rule in each interval. The BACB TCO lists partial interval, whole interval, and momentary time sampling under A.2.
What does an interval recording calculator calculate?
This interval recording calculator calculates true duration, partial interval, whole interval, and momentary time sampling scores from 20 rows of ten 0/1 samples. The interval outputs are percentages of rows that meet each scoring rule.
Is interval recording the same as frequency?
No. Frequency counts each response occurrence, while interval recording summarizes whether each interval met a scoring rule. A high interval percentage can happen without knowing the exact number of responses.
Can the calculator choose the correct interval method?
No. The calculator compares scoring rules on the same modeled timeline. For exam practice, choose the method from the scenario wording; for real services, follow the supervisor's written plan.