Level
Level is where data points fall on the vertical axis of a graph, often summarized as the average value within a phase.
Level describes the general height of the data on the y-axis. One phase may show a high level of behavior (for example, around 15 hits per session) and another a low level (around 2). Level is usually summarized by the mean or median of the data in a phase, and sometimes a horizontal line is drawn at that value.
Comparing levels is one of the main ways to see the effect of an intervention. A clear change in level right after a phase change line, such as a drop from around 15 to around 3 hits, is easy to see and suggests that something changed when the intervention began. Analysts also look at the change from the last few points of one phase to the first few points of the next.
Level should be read together with trend and variability. Two phases can have the same mean level but very different patterns: one steady, one rising quickly, or one with wide swings. A mean level alone can hide those differences. RBTs who notice a change in level, especially a sudden one, should report it to the supervisor along with any events that might explain it.
Example and non-example
| Example | During baseline a student completes about 4 problems per session; after the token system starts, the data sit around 12 problems per session. The level has increased. |
|---|---|
| Non-example | Data that start at 4 problems and climb steadily to 12 by the end of the phase show a trend, not a stable level. |
Don't confuse it with
| Trend | Level is the height of the data on the y-axis; trend is the direction they are moving over time. |
|---|---|
| Variability | Level is the typical value; variability is how far individual points spread from it. |
Test yourself
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Question 1How do the intervention data compare with the baseline data?
Number of instances of screaming by Session: 1: 8, 2: 9, 3: 8, 4: 9, 5: 8, 6: 3, 7: 2, 8: 3, 9: 2, 10: 3. Phases: Baseline from session 1, Intervention from session 6. Show answer
C: They are at a lower level, with little trend. Both phases are fairly flat, but the intervention data sit well below the baseline data. That is a change in level between phases.
- A: The intervention points are lower on the vertical axis than the baseline points.
- B: The intervention data stay flat rather than rising.
- D: The intervention data are clearly lower than the baseline data.
Task A.7 · 40-hour curriculum section C
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Question 2This graph shows a skill being taught. What has happened in the most recent sessions?
Percentage of trials correct by Session: 1: 20, 2: 35, 3: 50, 4: 60, 5: 60, 6: 60, 7: 60, 8: 60. Phases: Intervention from session 1. Show answer
C: Progress has leveled off. After rising early on, the data path has stayed flat for several sessions. The skill is no longer improving, which is a plateau worth reporting to the supervisor.
- A: The last several points are flat, not rising.
- B: The recent points have not dropped.
- D: The recent points are all the same value, which is no variability.
Task A.7 · 40-hour curriculum section C
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Question 3Which best describes these data?
Number of instances of biting by Session: 1: 3, 2: 4, 3: 3, 4: 15, 5: 3, 6: 4, 7: 3. Phases: Intervention from session 1. Show answer
C: Stable and low, except for one session. Every session but one is at about the same low value. One unusually high point does not create a trend; the RBT should check it against the data sheet and report it.
- A: The data return to the low level after the high point, so they do not rise overall.
- B: The values before and after the high point are about the same.
- D: Only one session differs; the rest are close together.
Task A.7 · 40-hour curriculum section C
Answer every question to see your score.
On the RBT exam
This term belongs to task A.7 Identifying trends in graphed data in content area A, Data Collection and Graphing, which is 13 of the 75 scored questions.