des_gs_pois() determines multi-stage group-sequential multi-arm
clinical trial designs assuming the primary outcome variable is Poisson
distributed. It computes required design components and returns information
on key operating characteristics.
des_gs_pois(
K =2,
J =2,
alpha =0.025,
beta =0.1,
lambda0 =5,
delta1 =1,
delta0 =0,
ratio =1,
power ="marginal",
stopping ="simultaneous",
type ="variable",
fshape ="pocock",
eshape ="pocock",
ffix =-3,
efix =3,
integer =F,
summary =F)
Arguments
K
A numeric indicating the chosen value for
K, the (initial) number of experimental
treatment arms. Defaults to 2.
J
A numeric indicating the chosen value for
J, the (maximum) number of allowed
stages. Defaults to 2.
alpha
A numeric indicating the chosen value for
α, the significance level
(family-wise error-rate). Defaults to 0.025.
beta
A numeric indicating the chosen value for
β, used in the definition of
the desired power. Defaults to 0.1.
lambda0
A numeric indicating the chosen value for
λ0, the
event rate in the control arm. Defaults to 5.
delta1
A numeric indicating the chosen value for
δ1, the
'interesting' treatment effect. Defaults to 1.
delta0
A numeric indicating the chosen value for
δ0, the
'uninteresting' treatment effect. Defaults to 0.
ratio
A numeric indicating the chosen value for
r, the stage-wise allocation ratio to
present experimental arms. Defaults to 1.
power
A character string indicating the chosen type of
power to design the trial for. Can be "disjunctive" or
"marginal". Defaults to "marginal".
stopping
A character string indicating the chosen type
of stopping rule. Can be "separate" or "simultaneous". Defaults
to "simultaneous".
type
A character string indicating the choice for the
stage-wise sample size. Can be "variable" or "fixed". Defaults
to "variable".
fshape
A character string indicating the choice for the
futility (lower) stopping boundaries. Can be any of "fixed",
"obf", "pocock", and "triangular". Defaults to
"pocock".
eshape
A character string indicating the choice for the
efficacy (upper) stopping boundaries. Can be any of "fixed",
"obf", "pocock", and "triangular". Defaults to
"pocock".
ffix
A numeric indicating the chosen value for the fixed
interim futility bounds. Only used when fshape = "fixed". Defaults to
"-3".
efix
A numeric indicating the chosen value for the fixed
interim efficacy bounds. Only used when eshape = "fixed". Defaults to
"3".
integer
A logical variable indicating whether the
computed possible sample sizes required in each arm in each stage should be
forced to be whole numbers. Defaults to FALSE. WARNING: If you set
integer = TRUE and ratio != 1, obscure results can occur due to
difficulties in identifying a suitable whole number sample size that meets
the allocation ratio requirement.
summary
A logical variable indicating whether a summary
of the function's progress should be printed to the console. Defaults to
FALSE.
Value
A list, with additional class
"multiarm_des_gs_pois", containing the following elements:
A tibble in the slot $opchar summarising the
operating characteristics of the identified design.
A tibble in the slot $pmf_N summarising the
probability mass function of the random required sample size under key
scenarios.
A numericvector in the slot $e
specifying e, the trial's
efficacy (upper) stopping boundaries.
A numericvector in the slot $f
specifying f, the trial's
futility (lower) stopping boundaries.
A numeric in the slot $maxN specifying
max N, the trial's maximum required
sample size.
A numeric in the slot $n_factor, for internal use
in other functions.
A numeric in the slot $n1 specifying
n1, the total sample size
required in stage one of the trial.
A numeric in the slot $n10 specifying
n10, the sample size
required in the control arm in stage one of the trial.