True strength index¶
A bounded momentum oscillator formed by double-smoothing price change and absolute price change and taking their ratio to indicate trend direction and relative momentum.
Core Idea¶
The true strength index is a technical indicator equal to double-smoothed momentum divided by double-smoothed absolute momentum, commonly scaled by one hundred. Smoothing suppresses high-frequency noise while the absolute-change denominator normalizes signed momentum, producing an oscillator whose sign and crossovers are interpreted as trend signals. The abstraction is therefore identified by a declared carrier, a transformation or constraint over that carrier, and an invariant that tells an analyst whether the named structure is genuinely present.
The load-bearing residual is not the broad topic of technical analysis. It is double-smoothed normalized momentum oscillator associated with William Blau. That residual remains recognizable when examples, notation, scale, or implementation change, but it disappears if the carrier is mistyped, the condition that price source, smoothing periods, initialization, scaling and missing-value handling are fixed before comparing values fails, a neighboring object is substituted, or notation and topical resemblance replace the constitutive test.
Scope of Application¶
True strength index belongs to technical analysis and is useful where the analyst can specify a price series, one-period changes, absolute changes, two exponential-smoothing parameters, numerator and denominator, scaled ratio, signal line and interpretation thresholds, then evaluate price source, smoothing periods, initialization, scaling and missing-value handling are fixed before comparing values. The scope is broad within that domain but bounded by the need for price source, smoothing periods, initialization, scaling and missing-value handling are fixed before comparing values. This is a descriptive market indicator, not individualized investment advice or a claim of predictive efficacy.
Clarity¶
The abstraction clarifies a crowded vocabulary by making price source, smoothing periods, initialization, scaling and missing-value handling are fixed before comparing values the center of the account. A claim should name the carrier, the governing operation or relation, the applicable assumptions, and the recognition test. A bare label is insufficient because the name True strength index can be used for a formal identity, an implementation, or a neighboring result unless carrier and convention are stated.
Manages Complexity¶
Without the abstraction, an analyst must reason directly over many local details: the carrier roles, admissibility assumptions, competing conventions, derived invariants, boundary cases, and proof or validation obligations specific to True strength index. True strength index compresses them into the roles in the structural signature. That compression permits comparison across instances without erasing the variables that determine validity. It also exposes which details may be varied safely and which are constitutive.
Abstract Reasoning¶
- Identify the carrier. State what the elements, states, objects, or observations are: a price series, one-period changes, absolute changes, two exponential-smoothing parameters, numerator and denominator, scaled ratio, signal line and interpretation thresholds. Reject examples whose alleged carrier belongs to a different problem. 2. Lock the constitutive rule. Express price source, smoothing periods, initialization, scaling and missing-value handling are fixed before comparing values independently of one notation or implementation.
Knowledge Transfer¶
Knowledge transfers strongly among subfields of technical analysis because they reuse a price series, one-period changes, absolute changes, two exponential-smoothing parameters, numerator and denominator, scaled ratio, signal line and interpretation thresholds, Smoothing suppresses high-frequency noise while the absolute-change denominator normalizes signed momentum, producing an oscillator whose sign and crossovers are interpreted as trend signals., and type the carrier, state every parameter and convention in the definition, test that price source, smoothing periods, initialization, scaling and missing-value handling are fixed before comparing values, compare the nearest accepted identity, and report counterexamples, uncertainty, and limiting cases.
Relationships to Other Abstractions¶
Current abstraction True strength index Domain-specific
Parents (1) — more general patterns this builds on
-
True strength index is a kind of Measurement Prime
The proposed strict upward parent is
prime:measurement.
Hierarchy path (1) — routes to 1 parentless root
- True strength index → Measurement
Neighborhood in Abstraction Space¶
True strength index sits in a moderately populated region (52nd percentile for distinctiveness): it has near-neighbors but no dense thicket of look-alikes.
Family — Financial Risk & Market Indicators (29 abstractions)
Nearest neighbors
- Technical analysis — 0.90
- Williams %R — 0.89
- Parabolic SAR — 0.88
- Unevenly spaced time series — 0.88
- Standard score — 0.87
Computed from structural-signature embeddings · 2026-09-08