The effect can be given as proportion of events in the experimental group (pH1), the risk difference (rdH1), risk ratio (rrH1) or odds ratio (orH1).
Usage
simSafetyStop(
nevents,
pH0 = 0.5,
alpha_test = 0.025,
pH1 = NULL,
rrH1 = NULL,
orH1 = NULL,
rdH1 = NULL,
r0 = NULL,
n = NULL,
icc = NULL,
correct = TRUE
)Arguments
- nevents
vector with number of events at which an interim analysis is done
- pH0
proportion of events in the experimental arm under the null hypothesis, typically based on randomization ratio (e.g. 0.5 for a 1:1 randomization)
- alpha_test
nominal alpha level for binomial exact test
- pH1
proportion of events in the experimental arm under the alternative hypothesis
- rrH1
risk ratio (experimental / control).
- orH1
risk ratio (experimental / control). Requires the control proportion (r0).
- rdH1
risk difference (experimental - control). Requires the control proportion (r0) and the number of participants (n).
- r0
risk in the control arm. Required if the effect is given as risk difference or odds ratio.
- n
total number of participants. Required if the effect is given as risk difference.
- icc
intraclass correlation if there is more than one event per patient
- correct
logical, whether to use icc for boundary construction
Value
list with a dataframe with number of events in each group plus upper limit for stopping and indicator for whether stopped, plus indicators number of stops and time points at first stop
Examples
set.seed(1)
simSafetyStop(nevents=seq(10,100,by=10),pH0 = 0.5, pH1 = 0.6, alpha_test=0.025)
#> $tests
#> nevents n1 n0 ulim out
#> 1 10 5 5 9 FALSE
#> 2 20 10 10 15 FALSE
#> 3 30 17 13 21 FALSE
#> 4 40 23 17 27 FALSE
#> 5 50 27 23 33 FALSE
#> 6 60 35 25 39 FALSE
#> 7 70 41 29 44 FALSE
#> 8 80 46 34 50 FALSE
#> 9 90 53 37 55 FALSE
#> 10 100 57 43 61 FALSE
#>
#> $nstop
#> [1] 0
#>
#> $tstop
#> [1] NA
#>
set.seed(1)
simSafetyStop(nevents=seq(10,100,by=10),pH0 = 0.5, rrH1 = 0.6/(1-0.6), alpha_test=0.025)
#> $tests
#> nevents n1 n0 ulim out
#> 1 10 5 5 9 FALSE
#> 2 20 10 10 15 FALSE
#> 3 30 17 13 21 FALSE
#> 4 40 23 17 27 FALSE
#> 5 50 27 23 33 FALSE
#> 6 60 35 25 39 FALSE
#> 7 70 41 29 44 FALSE
#> 8 80 46 34 50 FALSE
#> 9 90 53 37 55 FALSE
#> 10 100 57 43 61 FALSE
#>
#> $nstop
#> [1] 0
#>
#> $tstop
#> [1] NA
#>