Rate calculator (responses per minute or hour)
Rate is the count of a behavior divided by the time you observed it. Enter both and the calculator gives the rate per minute and per hour, with the working.
How to calculate rate
Rate = count ÷ observation time. Convert the time to the unit you want the answer in first. For a rate per hour, divide by the time in hours; for a rate per minute, divide by the time in minutes.
Example: a client aggresses 15 times in a 90-minute session. 90 minutes is 1.5 hours, so the rate is 15 ÷ 1.5 = 10 per hour. Per minute, it's 15 ÷ 90 ≈ 0.17.
A quick check: if the session was longer than an hour, the hourly rate must be smaller than the count; if it was shorter, larger.
Why rate instead of a count
A count of 12 means something different in a 30-minute session (24 per hour) than in a 3-hour session (4 per hour). When observation periods vary, only rate lets your supervisor compare sessions and see whether the behavior is changing. If every session is exactly the same length, the count and the rate tell the same story.
Common mistakes
- Dividing by minutes when the question asks for a rate per hour (or the other way round).
- Using the scheduled session length instead of the time you actually observed, for example after the client left early.
- Counting a behavior that has no clear start and end, such as being out of seat: that calls for duration, not rate.
Practice problems
| Problem | Answer |
|---|---|
| A client asks for help 18 times in a 45-minute session. What is the rate per hour? | 45 minutes is 0.75 hours: 18 ÷ 0.75 = 24 per hour. |
| A student calls out 6 times in 20 minutes. What is the rate per minute? | 6 ÷ 20 = 0.3 per minute (18 per hour). |
| Session 1: 12 elopements in 2 hours. Session 2: 9 in 1 hour. Which session had more elopement? | Session 2: 9 per hour against 6 per hour, although its count is lower. |
| A client engages in 40 vocal stereotypy responses over a 4-hour day. Rate per hour? | 40 ÷ 4 = 10 per hour. |
On the RBT exam
This calculator practises task A.6 Calculating and summarizing data. On the exam you get a dry-erase board but no calculator, so once you've checked a few answers here, practise doing them by hand.