FTB-C000467 / Implementation concept

True Range First-Bar Policy

True Range First-Bar Policy declares whether the first row is unavailable or falls back to its high-low span.

Also known asTR index-zero policy

Definitions

In plain terms

There is no previous close at index zero, so implementations must choose and document how readiness begins.

Technical

TA-Lib leaves the first value unavailable; this project's D07-F04 contract publishes high minus low at index zero.

Scope

Neither policy may be mixed silently because it shifts downstream ATR seeds and first-ready indexes.

Examples

  • A reviewer traces True Range First-Bar Policy from aligned inputs through its first-ready row and edge cases before accepting a displayed value.

Common misconceptions

  • Neither policy may be mixed silently because it shifts downstream ATR seeds and first-ready indexes.

Concept relationships

Where this concept is used

Evidence and governance

  1. True Range TA-Lib · first party technical publication

    Supports: preferred label, short definition, technical definition

    Limits: TA-Lib leaves the first row unavailable; the local D07 contract explicitly uses a high-low fallback.

  2. TA-Lib True Range Reference Implementation TA-Lib · first party technical publication

    Supports: preferred label, short definition, technical definition

    Limits: Library control flow does not prescribe the local diagnostic driver label or its author-defined tie priority.

Reviewed by
fintech-builder-batch-009
Last reviewed
2026-07-30
Next review
2027-07-30
Record status
published