Question: Why should a team inspect mistakes component by component before investing large amounts of time in improving one stage of a multi-step system? Explain how that inspection helps decide where to work first.

Sample answer: When a system has two stages, such as a front-end detector and a downstream classifier, a wrong output may come from the first stage, the second stage, or both. Reviewing a sample of errors one at a time lets the team assign each failure to the stage most likely responsible. That tally is useful because either stage might require a huge engineering effort, and the team does not want to spend that effort on the part that contributes little to the final mistakes. By measuring where the errors originate, the team can put its energy into the stage that appears to be driving the largest share of failures.

Key points:

• A multi-step model can fail in more than one component
• Individual mistakes should be traced to the stage or stages that caused them
• This review prevents wasting long periods improving the wrong part
• The error tally shows which stage deserves priority
• Manual inspection of misclassified examples is the method used

Rubric: Full credit explains that component-by-component error analysis assigns mistakes to specific stages, notes that either stage could consume major effort to improve, and states that the resulting attribution helps choose the highest-priority component.