Pilot Study Sample Size Precision Calculator

A Shiny app for calculating confidence intervals and margins of error for pilot study sample sizes. Helps researchers plan feasibility studies and generate grant text.

Quick Start

# Install dependencies
install.packages("shiny")

# Run the app
shiny::runApp("app.R")

# Run tests (optional)
source("run_tests.R")

Usage

Study Design Tab:

• Enter participants to approach, enrollment rate, adherence rate, attrition rate
• Get expected sample sizes and margins of error
• Switch to "Grant Text" tab for ready-to-copy grant language

Direct Calculator Tab:

• Enter any sample size and rate
• Get immediate margin of error calculation

Example

With 60 participants approached at 50% enrollment, 90% adherence, 10% attrition:

• Expected enrolled: 30 participants
• Expected completed: 27 participants (81% completion rate)
• Margins of error: ±18.0% enrollment, ±15.1% completion

Testing

source("run_tests.R")  # Returns PASS/FAIL summary

Files

• app.R - Main Shiny application
• run_tests.R - Test runner with pass/fail
• tests/ - Comprehensive test suite