underpowered-trial

Perform reverse power calculations and confidence interval analysis on negative clinical trials.

Updated Aug 27, 2026
One-click install
npx skills add https://github.com/j-walheim/Critical-AI-Scientist --skill underpowered-trial
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: underpowered-trial
Source: https://github.com/j-walheim/Critical-AI-Scientist/tree/main/agent_definition/.claude/skills/underpowered-trial
Command: npx skills add https://github.com/j-walheim/Critical-AI-Scientist --skill underpowered-trial

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires statsmodels, numpy, matplotlib, pandas, and includes scripts (resource) and references (resource) and assets (resource) components.

What problem does it solve?

This Skill helps determine if a "negative" clinical trial was truly negative or if it was underpowered, potentially hiding a real treatment effect.

Core Features & Use Cases

  • Reverse Power Calculation: Calculates the minimum detectable effect size for a given trial's sample size and alpha.
  • Post-Hoc Power Analysis: Assesses the power of the trial to detect the observed effect size (with caveats).
  • Confidence Interval Analysis: Critically evaluates if the CI includes clinically meaningful differences or the null.
  • Confirmatory Trial Planning: Estimates the required sample size for a future trial based on observed (and shrunk) effect sizes.
  • Use Case: A competitor's drug failed in Phase 2, with a p-value of 0.08. Use this Skill to analyze if the trial was truly underpowered and if a larger Phase 3 trial is warranted, or if the drug likely doesn't work.

Quick Start

Analyze the provided trial data to determine if it was underpowered and assess the need for a confirmatory trial.

Frequently Asked Questions about underpowered-trial

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I determine if a negative clinical trial was underpowered or if the drug truly doesn't work?

To determine if a negative clinical trial was underpowered, you can perform reverse power calculations and confidence interval analysis to find the minimum detectable effect size for the trial's sample size. This distinguishes genuine missed opportunities from failed hypotheses.

What is reverse power calculation in clinical trial analysis?

Reverse power calculation is a statistical analysis technique that calculates the minimum detectable effect size for a given clinical trial's sample size and alpha level. It helps assess the credibility of claims that a trial was underpowered due to insufficient sample size.

How do I calculate the required sample size for a confirmatory clinical trial based on a Phase 2 failure?

You can calculate the required sample size for a confirmatory clinical trial by estimating it based on the observed effect sizes and applying shrinkage. This analysis evaluates the feasibility of moving a drug from a failed Phase 2 trial to a larger Phase 3 study.

Can I use statsmodels and pandas for post-hoc power analysis on clinical trial data?

Yes, you can use statsmodels and pandas for post-hoc power analysis on clinical trial data. The analysis assesses the trial's power to detect the observed effect size while critically evaluating if confidence intervals include clinically meaningful differences or the null.

What are the limitations of using post-hoc power analysis on failed drug development trials?

A key limitation of post-hoc power analysis on failed drug development trials is that it must be interpreted with caveats. Confidence interval analysis is required alongside it to critically evaluate whether the interval includes clinically meaningful differences rather than relying solely on post-hoc power.

When do I need confidence interval analysis for hypothesis testing in drug development?

You need confidence interval analysis for hypothesis testing in drug development when evaluating if a negative trial's results include clinically meaningful differences or the null. This analysis helps uncover hidden signals in prior trials to determine if a confirmatory trial is warranted.