Case context: You are analyzing errors in a warehouse robot pipeline with three stages: (1) recognize aisle markers, (2) estimate shelf positions, and (3) choose a driving route. In the original order, A = recognize aisle markers, B = estimate shelf positions, and C = choose a driving route. Someone proposes swapping A and B. After the swap, the error-attribution percentages change a little, and they worry that the analysis is no longer trustworthy.

Question: Decide whether their worry is justified. Explain whether the swap breaks the DAG structure and what the small numerical changes mean for the usefulness of the analysis.

Sample answer: Their worry is not justified. If recognizing aisle markers and estimating shelf positions do not depend on one another, then they can be computed in either order without breaking the directed acyclic graph structure. The route-planning step still uses the outputs of the earlier stages, so the pipeline remains valid. A small change in the attribution numbers is expected after reordering independent steps, but the overall conclusions about where errors come from are still useful for deciding what to improve.

Key points:

• Swapping two independent stages does not break the DAG.
• The downstream route-planning step still depends on earlier outputs.
• Small shifts in attribution values do not make the analysis meaningless.

Rubric: The student's response should say the concern is misplaced, note that the two swapped stages are independent, confirm that the overall DAG remains valid, and explain that minor numerical changes do not remove the guidance provided by the analysis.