# Power Analysis

Compute statistical power, required sample size, and minimum detectable effect (MDE)...

- Repository: https://github.com/pedrohcgs/claude-code-my-workflow (1676 stars)
- Category: Design
- License: MIT
- Last updated: 2026-09-27
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add pedrohcgs/claude-code-my-workflow --skill power-analysis -g -a claude-code -y`
Codex: `npx skills add pedrohcgs/claude-code-my-workflow --skill power-analysis -g -a codex -y`
Cursor: `npx skills add pedrohcgs/claude-code-my-workflow --skill power-analysis -g -a cursor -y`
Gemini CLI: `npx skills add pedrohcgs/claude-code-my-workflow --skill power-analysis -g -a gemini-cli -y`

## Description

Compute statistical power, required sample size, and minimum detectable effect (MDE) for a study design, then write a registry-ready power section. Handles two-arm RCTs (with clustering / ICC and unequal allocation), multiple-arm corrections, and a simulation-based power option for non-standard designs (DiD/event-study, IV, panel). Use when user says "power analysis", "power calculation", "MDE", "minimum detectable effect", "how big a sample do I need", "is my study powered", "power for an RCT", or when /preregister needs a power section for an experiment. Produces a power/MDE table, power curves, and a methods paragraph to paste into a preregistration.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# `/power-analysis`, Power / MDE for study design

Compute the three interlocking quantities of an ex-ante design calculation, **power**, **required N**, and **minimum detectable effect (MDE)**, and emit a power section the user can paste straight into a preregistration. Analytical for standard designs; simulation-based (reusing the `/simulation-study` harness pattern) for non-standard ones.

**Core principle:** a power calculation is a *design-time commitment made before the data exist*. Fix any two of {effect size, N, power} and solve for the third; never back out a "power" number from a realised estimate (that is post-hoc power, and it is uninformative, see "What this skill does NOT do").

## When to use

- **Before launching an RCT / field / survey experiment**, to choose N (or clusters) for a target MDE at 80, 90% power.
- **Invoked by [`/preregister`](../preregister/SKILL.md) for RCTs**, the AEA RCT Registry and most IRBs require a power/MDE justification; `/preregister`'s `aea-rct` style follows this skill's phases to fill that section (this skill is user-invoked only, so it is read and followed, not called).
- **During R&R**, when a referee asks "was this study adequately powered to detect the effect you claim?"
- **Designing a Monte Carlo**, to set `R` and sample sizes before handing off to `/simulation-study`.

## Inputs

`$ARGUMENTS` may carry flags; missing pieces are elicited in Phase 0.

- `--mode mde|n|power`, solve for MDE given N+power, N given MDE+power, or power given N+MDE. Default `mde`.
- `--design rct|cluster|multiarm|sim`, two-arm RCT, clustered RCT (ICC), multiple arms, or simulation-based. Default inferred from the elicited design.
- `--input <path>`, a spec from [`/interview-me`](../interview-me/SKILL.md) (under `quality_reports/specs/`) to pull the RQ, outcome, and design from.

## Workflow

### Phase 0, Elicit the design

Gather the design parameters; **ask once** for anything missing rather than fabricating. Required:

The rest: https://github.com/pedrohcgs/claude-code-my-workflow/blob/HEAD/.claude/skills/power-analysis/SKILL.md