gsDesign (version 3.5.0)

toInteger: Translate group sequential design to integer events (survival designs) or sample size (other designs)

Description

Translate group sequential design to integer events (survival designs) or sample size (other designs)

Usage

toInteger(x, ratio = 0, roundUpFinal = TRUE)

Value

An object of class gsDesign with integer vector for n.I.

Arguments

x

An object of class gsDesign.

ratio

Integer indicating randomization ratio; not used for time-to-event outcome; see details.

roundUpFinal

Final value in returned n.I rounded up if TRUE; otherwise, just rounded.

Details

Note that if ratio is 0, rounding for n.I is done to the nearest integer. For input x of class gsSurv (time-to-event outcome), ratio is taken from the input x rather than the value provided in the ratio argument. For cases other than gsSurv class, rounding of final.

Examples

# The following code derives the group sequential design using the method
# of Lachin and Foulkes

x <- gsSurv(
  k = 3,                 # 3 analyses
  test.type = 4,         # Non-binding futility bound 1 (no futility bound) and 4 are allowable
  alpha = .025,          # 1-sided Type I error
  beta = .1,             # Type II error (1 - power)
  timing = c(0.45, 0.7), # Proportion of final planned events at interims
  sfu = sfHSD,           # Efficacy spending function
  sfupar = -4,           # Parameter for efficacy spending function
  sfl = sfLDOF,          # Futility spending function; not needed for test.type = 1
  sflpar = 0,            # Parameter for futility spending function
  lambdaC = .001,        # Exponential failure rate
  hr = 0.3,              # Assumed proportional hazard ratio (1 - vaccine efficacy = 1 - VE)
  hr0 = 0.7,             # Null hypothesis VE
  eta = 5e-04,           # Exponential dropout rate
  gamma = 10,            # Piecewise exponential enrollment rates
  R = 16,                # Time period durations for enrollment rates in gamma
  T = 24,                # Planned trial duration
  minfup = 8,            # Planned minimum follow-up
  ratio = 3              # Randomization ratio (experimental:control)
)
# Convert bounds to exact binomial bounds
toInteger(x, ratio = 3)