twoSurvSampleSizeNI: Sample Size Calculation for Two-Group Non-Inferiority...

In rashnu: Balanced Sample Size and Power Calculation Tools

Sample Size Calculation for Two-Group Non-Inferiority Survival Study

Description

Calculates the required sample size and expected event numbers for a non-inferiority trial with two survival curves, using piecewise integration of hazard functions under exponential survival assumptions.

Usage

twoSurvSampleSizeNI(
  syear,
  yrsurv1,
  yrsurv2,
  alloc,
  accrualTime,
  followTime,
  alpha,
  power,
  margin
)

Arguments

syear	Survival time horizon (e.g., median survival time) in years.
yrsurv1	Survival probability of the standard group at syear.
yrsurv2	Survival probability of the test group at syear.
alloc	Allocation ratio (Test / Standard), e.g., 1 means equal allocation.
accrualTime	Duration of patient accrual period.
followTime	Follow-up period after last patient is accrued.
alpha	One-sided significance level (e.g., 0.025).
power	Desired statistical power (e.g., 0.8).
margin	Non-inferiority margin for hazard ratio (HR).

Value

A list containing:

Sample_size_of_standard_group

Required sample size in the standard group.

Sample_size_of_test_group

Required sample size in the test group.

Total_sample_size

Total sample size.

Expected_event_numbers_of_standard_group

Expected number of events in the standard group.

Expected_event_numbers_of_test_group

Expected number of events in the test group.

Total_expected_event_numbers

Total number of expected events across both groups.

References

Jung SH, Chow SC. (2012). On sample size calculation for comparing survival curves under general hypothesis testing. Journal of Biopharmaceutical Statistics, 22(3), 485–495.

Web calculator (Non-Inferiority): https://nshi.jp/en/js/twosurvyrni/

Examples

twoSurvSampleSizeNI(
  syear = 2,
  yrsurv1 = 0.7,
  yrsurv2 = 0.65,
  alloc = 1,
  accrualTime = 1,
  followTime = 1,
  alpha = 0.025,
  power = 0.8,
  margin = 1.3
)

rashnu documentation built on June 18, 2025, 5:08 p.m.