# Delta-If-Present Calculations for Missing Signals

## Status
NOT_FOUND

## Description
The advisory proposed computing "delta if present" values showing what would change if missing signals arrived (TSF-004). This was marked TODO and has not been implemented.

## Why Not Implemented
- The specific "delta-if-present" calculation (TSF-004) for showing hypothetical score changes is not implemented as a standalone feature
- However, related infrastructure exists in the Policy Determinization module:
  - `src/Policy/__Libraries/StellaOps.Policy.Determinization/Models/SignalGap.cs` -- models for missing/gap signals
  - `src/Policy/__Libraries/StellaOps.Policy.Determinization/Scoring/UncertaintyScoreCalculator.cs` -- calculates uncertainty from missing signals
  - `src/Policy/__Libraries/StellaOps.Policy.Determinization/Scoring/PriorDistribution.cs` -- prior distributions for gap handling
  - `src/Policy/__Libraries/StellaOps.Policy.Determinization/DeterminizationOptions.cs` -- configuration for determinization behavior
  - `src/Policy/StellaOps.Policy.Engine/Simulation/RiskSimulationBreakdown.cs` -- risk simulation with breakdown
  - Tests: `src/Policy/__Tests/StellaOps.Policy.Engine.Tests/Simulation/RiskSimulationBreakdownServiceTests.cs`
- The Determinization module handles missing signals by computing uncertainty scores but does not project "what would change if signal X arrived" as a delta preview
- Graph module also tracks missing signals: `src/Graph/__Libraries/StellaOps.Graph.Core/ICveObservationNodeRepository.cs`

## Source
- Feature matrix scan

## Notes
- Module: Policy
- Modules referenced: `src/Policy`
- Related: `src/Policy/__Libraries/StellaOps.Policy.Determinization/` (uncertainty scoring for gaps)