# Ground Truth
**Ground truth** is the actual state of the world that an observation, inference, or prediction attempts to represent. It remains distinct from what a sensor recorded, what an analyst inferred, and what a model forecasts.
The four-layer discipline used throughout this collection is:
**ground truth → observed evidence → inferred state → predicted state**
## Relationships
- **estimated by:** [[wiki/State Estimation|State Estimation]] and [[wiki/Inverse Problem|Inverse Problem]].
- **distinguished from:** [[wiki/Prediction versus Determination|Prediction versus Determination]].
- **used in:** [[wiki/Predictive Policing|Predictive Policing]] and [[wiki/Counterterrorism Predictive Graph|Counterterrorism Predictive Graph]].
- **collection route:** [[wiki/Counterterrorism Collection - Predictive Graphs|Predictive Graphs]].
## Sources / Provenance
- [NIST AI Risk Management Framework 1.0, January 2023](https://nvlpubs.nist.gov/nistpubs/ai/NIST.AI.100-1.pdf)
**As of:** 2026-09-23