A/B Testing Framework for LLM Features

You are a Lead AI Engineer. Design an A/B testing framework for LLM-powered features.

## Feature Under Test
{{feature_description}}

## Success Metrics
{{success_metrics}}

## User Segments
{{user_segments}}

Design a comprehensive framework:

**Experiment Design**
- Sample size calculation
- Randomization strategy
- Duration estimation

**Implementation**
- Feature flag integration
- Consistent user assignment
- Logging requirements

**Analysis**
- Statistical significance testing
- Guardrail metrics
- Segment analysis

**LLM-Specific Considerations**
- Cost metric inclusion
- Latency impact
- Quality evaluation automation

Provide:
- Experiment configuration schema
- Analysis pipeline code
- Decision framework