Description Usage Arguments Value Examples
simVBIA
simulates runs
adaptive trials with
blinded interim analysis and assesses the bias of the variance
and mean estimates. Sample size review is performed either using
an interim estimate of the pooled variance that is adjusted
based on the assumed effect size or the uncorrected lumped variance.
1 2 3 |
delta |
true effect size |
sigma |
true standard deviation |
d |
assumed effect size |
n1 |
first stage sample size in treatment group |
alpha |
= .025 pre-specified alpha level |
beta |
pre-specified beta level |
v |
timing of interim analysis |
s |
assumed standard deviation, is more or less the same as n1 |
runs |
number of simulation runs |
n2 |
first stage sample size in control group |
n2min |
minimum secondstage sample size |
n2max |
maximum secondstage sample size |
fulldata |
return full data |
cf |
correction term added to the sample size rule |
If fulldata is FALSE
simVBIA returns a list with
the following items, summarizing the simulation results for
designs with sample size reassessment based on the adjusted
interim variance estimates:
lower.prob |
Coverage probability of the lower confidence bound |
upper.prob |
Coverage probability of the upper confidence bound |
total.prob |
Coverage probability of the two sided confidence interval |
mean.bias |
Bias of the mean estimate |
variance.bias |
Bias of the variance estimate |
ev |
Variance of the mean estimate as estimated from the adaptive trian |
exv |
Variance of the mean estimate of a fixed sample trial with corresponding sample size |
vm |
Variance of the mean estimate in the monte carlo sample |
root.mse |
Root mean squared error of the effect estimate |
mean.m1 |
Mean second stage sample size |
low.m1 |
Lower 10 percen quantile of second stage sample sizes |
n10 |
Probability that the second stage sample size is zero |
as well as results for designs with sample size reassessment based on unadjusted interim estimates:
uc.mean.bias |
Bias of the mean estimate |
uc.variance.bias |
Bias of the variance estimate |
uc.ev |
Variance of the mean estimate as estimated from the adaptive trian |
uc.exv |
Variance of the mean estimate of a fixed sample trial with corresponding sample size |
uc.vm |
Variance of the mean estimate in the monte carlo sample |
uc.root.mse |
Root mean squared error of the effect estimate |
uc.mean.m1 |
Mean second stage sample size |
uc.low.m1 |
Lower 10 percen quantile of second stage sample sizes |
uc.N10 |
Probability that the second stage sample size is zero |
tn1 |
mean(n1) |
1 | simVBIA(.5,1,1,n1=10,n2min=2,runs=1000)
|
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.