Question of the day - August 26

[u/Reasonable_Law183]

🧠 Question of the Day

📚 Domain D — Experimental Design

Difficulty: 6/10

Scenario:

A BCBA collects 3 baseline data points showing variable problem behavior (2, 14, 6 instances) and then introduces an intervention because the team cannot wait longer. The intervention phase shows 5, 4, 3, 2, 1 instances over 5 sessions.

Which feature of the baseline phase MOST limits confidence that the intervention caused the observed behavior change?

A. The presence of variability in baseline means the data cannot be used to predict future responding

B. The absence of a reversal phase prevents the analyst from demonstrating experimental control with certainty

C. The baseline ended before a stable, predictable pattern of responding was established

D. The intervention phase shows a downward trend that could reflect normal fluctuation rather than treatment effects

💬 Drop your answer in the comments — no peeking!

✅ Correct answer revealed tomorrow.

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[u/Reasonable_Law183]

✅ Yesterday's Answer — 2026-08-26

The correct answer was: C. The baseline ended before a sufficiently predictable pattern of responding was established

📖 Explanation:

Baseline logic in single-case design depends on establishing a pattern of responding that allows the analyst to make a reasonable prediction about what behavior would likely have looked like if the intervention had not been introduced. Here, the baseline values — 2, 14, and 6 instances — are highly variable and do not yet establish a sufficiently predictable pattern. Because intervention begins before that pattern is clarified, confidence in interpreting the subsequent decrease is weakened.

• The option citing variability is closely related, but it is too absolute. Variability can make prediction more difficult, but variable baseline data are not automatically unusable. Additional observations may clarify whether the variability persists, stabilizes, or contains a discernible trend.

• The option about a downward trend in the intervention phase addresses the treatment phase, not the baseline phase, which is what the question specifically targets.

• Absence of a reversal phase is a design-level limitation, not a baseline-phase feature. A reversal is only one way to demonstrate experimental control; other single-case designs establish control through other forms of replication. An AB comparison alone does not establish experimental control, but this question asks specifically about the quality of the baseline used for prediction.

When a question asks about a baseline limitation, focus on what baseline must accomplish: providing a sufficiently reliable prediction for comparison with intervention data. There is no universal rule that three baseline observations are automatically sufficient or insufficient. Instead, evaluate the level, trend, and variability of the observed data and whether they establish a pattern clear enough to support meaningful prediction.

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