We present a simple sample-size formula for weighted log-rank statistics applied to clustered survival data with variable cluster sizes and arbitrary treatment assignments within clusters. This ...

Health-related quality of life (HRQoL) instruments are increasingly used as outcome variables in clinical trials, leading to a requirement for sample size calculations based on these variables. This ...

Given the unacceptable quality of the sample size calculation of COVID-19 trials, I strongly suggest that all research teams include a statistician or invite a statistician to evaluate the ...