---
title: "Population Stability Index (PSI)"
type: concept
tags: [ml-ops, model-monitoring, drift]
sources: [specialized-model-qa]
last_updated: 2026-04-20
---

## Definition
Population Stability Index（PSI）用于衡量两个样本分布之间的变化程度，常见于模型监控与特征稳定性分析。

## Interpretation
- < 0.10：无显著偏移
- 0.10–0.25：中等偏移，需要调查
- ≥ 0.25：显著偏移，需要处理

## Use in Model QA
- 检测特征漂移
- 识别训练集与生产集分布差异
- 为复审与再训练提供量化证据

## Related Concepts
- [[Model Audit]]
- [[Calibration Testing]]
- [[Discrimination Metrics]]