# Randomization

> Implement proper randomization procedures for experiments. Use when: (1) Assigning participants to conditions, (2) Ensuring unbiased allocation, (3) Meeting CONSORT standards, (4) Pre-registration.

- Skill: `majiayu000/randomization` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add majiayu000/randomization`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/randomization/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Productivity
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/majiayu000/randomization

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# Randomization Skill

## Purpose
Implement proper random assignment to minimize selection bias.

## Randomization Methods

**1. Simple Randomization**
- Coin flip, random number generator
- Best for large samples (N>200)
- Risk of imbalance in small samples

**2. Block Randomization**
- Ensures equal group sizes
- Blocks of 4, 6, or 8
- Example: AABB, ABAB, BABA, BBAA

**3. Stratified Randomization**
- Balance prognostic factors
- Stratify by sex, age group, severity
- Then randomize within strata

**4. Minimization**
- Dynamic allocation
- Minimizes imbalance across factors
- Used in small trials

## Implementation

**Steps:**
1. Generate random sequence (with seed)
2. Document sequence generation
3. Implement allocation concealment
4. Execute randomization
5. Document actual allocation

**Example (Python):**
```python
import random
random.seed(12345)  # Document seed
sequence = ['A', 'B'] * 50  # 100 participants
random.shuffle(sequence)
```

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**Version:** 1.0.0