回溯：重新定义失败的算法

Backtracking in Product Development

When InterviewAI's first voice flow felt too slow, we didn't push forward in denial — we stepped back, simplified, and re-tested. Same for Band9AI writing feedback when an upgrade produced worse cohesion flags.

Documenting what you tried makes backtracking cheap. Moralizing dead ends makes it expensive.

Decision Search Tree (Conceptual)

{
  "decision_process": {
    "explore": "Try the promising path",
    "measure": "Did quality improve for real users?",
    "prune": "Abandon paths that fail the quality bar",
    "backtrack": "Return to last known-good approach",
    "commit": "Ship only after sustained improvement"
  }
}

Code Gives Second Chances

Engineering culture that rewards exploration with clean rollback beats culture that punishes wrong turns. Band9AI's methodology page exists because we document what we tried, what we pruned, and why — not just what shipped.

Backtracking for IELTS Retakes

A retake that repeats the same study plan is not learning — it is replaying a failed branch. Backtracking means naming the dead end (for example, memorized Part 2 scripts), returning to the decision point, and trying a different path with measurement.

Band9AI’s diagnostics exist to make those decision points visible: which criterion failed, under what pressure, and what to change before spending another exam fee.

Before another exam fee, name the failed branch in one sentence: which skill, which criterion, and whether time pressure was the limiter. Then change only that branch. A second attempt that repeats the same scripts is the same path, not a backtrack.