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Sample size calculation: Survival analysis (logrank test)

Command:Sample size
Next selectSurvival analysis (logrank test)

Description

Calculates the required sample size for the comparison of survival rates in two independent groups.

Required input

Example

Sample size calculation for survival analysis.

You are interested in detecting a difference between survival rates of 0.6 and 0.4. You plan to have twice as many cases in the first group as in the second group.

For α-level you select 0.05 and for β-level you select 0.20 (power is 80%).

Enter the values 0.6 and 0.4 for the Survival rates in Group 1 and Group 2, and enter 2 for the Ratio of sample sizes.

Results

After you click Calculate the program displays the required sample size.

In the example 129 cases are required in Group 1 and 65 cases in Group 2, giving a total of 194 cases.

A table shows the required total sample size for different Type I and Type II Error levels.

Literature

See also

Recommended book

Sample Size Tables for Clinical Studies
David Machin, Michael J. Campbell, Say-Beng Tan, Sze-Huey Tan

Buy from Amazon US - CA - UK - DE - FR - ES - IT

Sample Sizes for Clinical, Laboratory and Epidemiology Studies includes the sample size software (SSS) and formulae and numerical tables needed to design valid clinical studies. The text covers clinical as well as laboratory and epidemiology studies and contains the information needed to ensure a study will form a valid contribution to medical research.

The authors, noted experts in the field, explain step by step and explore the wide range of considerations necessary to assist investigational teams when deriving an appropriate sample size for their when planned study. The book contains sets of sample size tables with companion explanations and clear worked out examples based on real data. In addition, the text offers bibliography and references sections that are designed to be helpful with guidance on the principles discussed.