Definitions
In plain terms
It translates the abstract decay factor into an intuitive persistence horizon.
Technical
For decay factor lambda between zero and one, half-life equals log(0.5) divided by log(lambda); it is approximately 9.35 updates when n equals 14.
Scope
Half-life is not a finite expiry point because some geometric weight remains afterward.
Formula
ATR half-life = log(0.5) / log((n - 1) / n)h_{1/2}=\frac{\log(0.5)}{\log((n-1)/n)}| Symbol | Meaning | Unit |
|---|---|---|
n | ATR period | bars |
h_{1/2} | ATR state half-life | updates |
Output unit: updates
Examples
- A reviewer traces ATR Half-Life from aligned inputs through its first-ready row and edge cases before accepting a displayed value.
Common misconceptions
- Half-life is not a finite expiry point because some geometric weight remains afterward.
Concept relationships
Prerequisites
Where this concept is used
Evidence and governance
- Average True Range TA-Lib · first party technical publication
Supports: preferred label, short definition, technical definition, formula
Limits: Seed, smoothing convention, lookback, and missing-bar handling must be declared for reproducible use.
- TA-Lib Average True Range Reference Implementation TA-Lib · first party technical publication
Supports: preferred label, short definition, technical definition, formula
Limits: TA-Lib readiness follows its own unavailable-first-TR convention and therefore differs from the local alignment.
- Reviewed by
- fintech-builder-batch-009
- Last reviewed
- 2026-07-30
- Next review
- 2027-07-30
- Record status
- published