Sample Size Calculation Tools

Functions for sample size estimation and simulation in clinical trials. Includes methods for selecting the best group using the Indifference-zone approach, as well as designs for non-inferiority, equivalence, and negative binomial models. For the sample size calculation for non-inferiority of vaccines, the approach is based on Fleming, Powers, and Huang (2021) . The Indifference-zone approach is based on Sobel and Huyett (1957) and Bechhofer, Santner, and Goldsman (1995, ISBN:978-0-471-57427-9).

ssutil

ssutil is an R package providing a suite of tools for sample size estimation and power simulation in a variety of clinical trial designs. It includes methods for binomial, normal, and negative binomial endpoints, as well as support for equivalence and non-inferiority testing scenarios. It also includes functionality for power and sample size calculation for selecting the best group using the indifference-zone approach for normal and binomial outcomes.

Features

• Empirical power simulation for:
  • Binomial, normal, and negative binomial endpoints
  • Equivalence and non-inferiority designs
  • Best group selection using the indifference-zone approach for normal and binomial outcomes
• Sample size utilities for various design types

Installation

# Install from GitHub (requires remotes or devtools)
remotes::install_github("johnaponte/ssutil")

Vignettes

Learn how to use ssutil through these worked examples:

• Selection of the best group using indifference-zone approach for binomial outcomes

• Selection of the best group using indifference-zone approach for normal outcomes

• Equivalence Trials

• Negative Binomial Models

• Non-Inferiority Testing

• Power for Rare Events