SupProb: Superiority Probability

In PracticalEquiDesign: Design of Practical Equivalence Trials

Description

Probability of selecting the more effective treatment as pr(median2 - median1 >= margin) + 0.5 * pr(abs(median2 - median1) < margin).

Usage

SupProb(
  cens_prop,
  n,
  med1 = NULL,
  shape1 = NULL,
  rate1 = NULL,
  med2 = NULL,
  shape2 = NULL,
  rate2 = NULL,
  info_reps = 50,
  margin = 0,
  use_exp_calc = TRUE
)

Arguments

cens_prop	Expected censoring proportion.
n	Sample size.
med1	Median for treatment arm 1, assuming shape1 = 1. Overwrites shape and rate if supplied.
shape1	Shape parameter for arm 1.
rate1	Rate parameter for arm 1.
med2	Median for treatment arm 2, assuming shape2 = 1. Overwrites shape and rate if supplied.
shape2	Shape parameter for arm 2.
rate2	Rate parameter for arm 2.
info_reps	Replicates used for estimating the observed information matrix.
margin	Margin of practical equivalence.
use_exp_calc	If both shape parameters are 1, should the calculations be performed assuming an exponential distribution for the time to event in each arm? Default is TRUE.

Value

Numeric equivalence probability.

Examples

# Calculation in the case of exponentials with no margin.
prob <- SupProb(
  cens_prop = 0.15,
  n = 100,
  med1 = 9,
  med2 = 12,
)

# Calculation in the case of exponentials with a 2 month margin.
# The probability should be lower than in the absence of a margin.
prob <- SupProb(
  cens_prop = 0.15,
  n = 100,
  med1 = 9,
  med2 = 12,
  margin = 2
)

# Calculation in the case of Weibulls with a 2 month margin.
prob <- SupProb(
  cens_prop = 0.15,
  n = 100,
  shape1 = 2.8,
  rate1 = 0.10,
  shape2 = 4.0,
  rate2 = 0.08,
  margin = 2
)

PracticalEquiDesign documentation built on Dec. 6, 2021, 9:08 a.m.