Scoring band normalization and streak attribution policy

DEC-0051 - Scoring band normalization and streak attribution policy

Context

Score interpretation and streak counting had baseline rules, but boundary values and attribution semantics still caused ambiguity.

Decision

Scoring bands are finalized to:

• 0-19: chưa đạt
• 20-59: cần cải thiện
• 60-79: khá
• 80-99: giỏi
• 100: xuất sắc

Scoring normalization and completeness:

• For scaled tests, normalize by test max to percentage before band mapping.
• Objective unanswered items count as wrong.

Streak attribution:

• Day boundary uses user local timezone.
• Completion attribution uses submit timestamp.
• Single freeze auto-consumes on first missed day.

Decision Value

• Removes boundary confusion across skills and test formats.
• Aligns streak behavior with user expectation and timezone fairness.
• Keeps score feedback consistent and comparable in UX.

Rationale

Unified percent-band logic and submit-based day attribution are simple enough for users to understand and robust enough for analytics.