ADR-0002: Symmetric boost window

Status

Accepted

Context

A boost date ramps volume up before an event, peaks on the day, and ramps down after. The window is described by daysBefore and daysAfter. The original worked examples ended the ramp-down one day later than a symmetric reading of the counts predicted.

Decision

The window is symmetric. daysAfter is the count of ramp-down days after the peak, with the peak day excluded from both shoulders. For daysBefore 14, the ramp-up covers the 14 days ending the day before the peak; for daysAfter 6, the ramp-down covers the 6 days starting the day after the peak.

Consequences

• The math is predictable and matches daysBefore.
• The one-day-longer end dates in the original examples are not the behavior.
• The BoostCalculator.PercentOn function is unit-tested against both worked examples and the suppression case.

Alternatives considered

• An inclusive end that reproduces the original example end dates. Rejected as an off-by-one rather than an intended asymmetry.