Oncostat’s Sample Size Comparison

This repository presents a systematic comparison of sample size calculations implemented in R with those from two widely used commercial tools: East and nQuery.

R as an alternative to East and nQuery.

Below is a concise overview of the main findings from the Sample Size Comparison project.
The table compares, for each endpoint and design type, the statistical test used, and how well the implemented R calculations matched the software(East or nQuery) reference values.

Endpoints	Design type	Test	R/Software matching
survival	2‑Arm fixed design	Log‑rank	🟢 Perfect
survival	2‑Arm group‑sequential design	Log‑rank	🟡 Good
survival	1‑Arm fixed design	Log‑rank	🔵 Poor
Binary	2‑Arm fixed design	Exact	🟡 Good
Binary	2‑Arm fixed design	Z‑Pooled	🟢 Perfect
Binary	2‑Arm group‑sequential design	Z‑Pooled	🟢 Perfect
Binary	1‑Arm fixed design	Exact	🟡 Good
Binary	1‑Arm fixed design	1‑Arm Z test	🟢 Perfect

Legend:
🟢 Perfect = identical or extremely close values
🟡 Good = small but acceptable discrepancies
🔵 Poor = substantial differences requiring further investigation

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Website

Browse the interactive website to explore results, methodology, and reproducible R code.

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Slides (in french)

Slides from the 25/02/2026 presentation at Gustave Roussy

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R directory Structure

Quick overview of how the entire SSC project is organised:

• a central main.R file, from which the full pipeline is executed;
• modular comparison scripts, one per design;
• dedicated functions/ and wrappers/ directory for all helpers and wrappers;
• a small S7 layer holding the two core classes (ssc_design and ssc_results).

R/
├── init.R
├── main.R
├── comparison/
│   ├── comp_bin_fixed_exact.R
│   ├── comp_bin_fixed_pooled.R
│   ├── comp_bin_gs.R
│   ├── comp_bin_one_arm_exact.R
│   ├── comp_bin_one_arm.R
│   ├── comp_surv_fixed.R
│   ├── comp_surv_gs.R
│   └── comp_surv_one_arm.R
├── functions/
│   ├── checks.R
│   ├── e_ratio.R
│   ├── evaluate_relevancy.R
│   ├── helpers.R
│   ├── n_ratio.R
│   └── exact_wrapper.R
├── S7/
│   ├── generics.R
│   ├── ssc_design.R
│   └── ssc_results.R
├── side-analysis/
│   ├── bin2arms_exact.R
│   └── lakatos_n_lan.R
└── wrappers/
    ├── ahern_wrapper.R
    ├── bbssr_wrapper.R
    ├── exact_wrapper.R
    ├── gsdesign2_wrapper.R
    ├── oa2s_wrapper.R
    ├── rashnu_wrapper.R
    ├── rpact_wrapper.R
    └── sssas_wrapper.R

License

Sample Size Comparison © 2026 by Oncostat is licensed under CC BY 4.0