lakatosSampleSize {rashnu} | R Documentation |
Sample Size Calculation Using Lakatos Method for Survival Analysis
Description
Computes the required sample size and expected event numbers for two-group survival analysis using Lakatos' method under exponential survival assumptions and varying weight functions (log-rank, Gehan, Tarone-Ware).
Usage
lakatosSampleSize(
syear,
yrsurv1,
yrsurv2,
alloc,
accrualTime,
followTime,
alpha,
power,
method = c("logrank", "gehan", "tarone-ware"),
side = c("two.sided", "one.sided"),
b = 24
)
Arguments
syear |
Survival time horizon in years. |
yrsurv1 |
Survival probability of the standard group at |
yrsurv2 |
Survival probability of the test group at |
alloc |
Allocation ratio (Test / Standard). For equal allocation, use 1. |
accrualTime |
Accrual period duration. |
followTime |
Additional follow-up time after last patient is accrued. |
alpha |
Significance level (e.g., 0.05 for two-sided tests). |
power |
Desired statistical power (e.g., 0.8). |
method |
Weighting method for test statistic. One of |
side |
Type of test: |
b |
Number of time divisions per year for numerical integration (default = 24). |
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.
- Actual_power
Achieved power given the calculated sample size.
- error
(Optional) Error message when sample size cannot be calculated.
References
Lakatos E. (1988). Sample sizes based on the log-rank statistic in complex clinical trials. Biometrics, 44, 229–241.
Lakatos E, Lan KK. (1992). A comparison of sample size methods for the logrank statistic. Statistics in Medicine, 11(2), 179–191.
Web calculator (Superiority): https://nshi.jp/en/js/twosurvyr/
Examples
lakatosSampleSize(
syear = 2,
yrsurv1 = 0.7,
yrsurv2 = 0.6,
alloc = 1,
accrualTime = 1,
followTime = 1,
alpha = 0.05,
power = 0.8,
method = "logrank",
side = "two.sided"
)