test.surrogate {SurrogateRank}

Tests whether the surrogate is valid

Description

Calculates the rank-based test statistic for Y and the rank-based test statistic for S and the difference, delta, along with corresponding standard error estimates, then tests whether the surrogate is valid

Usage

test.surrogate(full.data = NULL, yone = NULL, yzero = NULL, sone = NULL, 
szero = NULL, epsilon = NULL, power.want.s = 0.7, u.y.hyp = NULL)

Arguments

full.data

either full.data or yone, yzero, sone, szero must be supplied; if full data is supplied it must be in the following format: one observation per row, Y is in the first column, S is in the second column, treatment group (0 or 1) is in the third column.

yone

primary outcome, Y, in group 1

yzero

primary outcome, Y, in group 0

sone

surrogate marker, S, in group 1

szero

surrogate marker, S, in group 0

epsilon

threshold to use for delta, default calculates epsilon as a function of desired power for S

power.want.s

desired power for S, default is 0.7

u.y.hyp

hypothesized value of u.y used in the calculation of epsilon, default uses estimated valued of u.y

Value

u.y

rank-based test statistic for Y

u.s

rank-based test statistic for S

delta

difference, u.y-u.s

sd.u.y

standard error estimate of u.y

sd.u.s

standard error estimate of u.s

sd.delta

standard error estimate of delta

ci.delta

1-sided confidence interval for delta

epsilon.used

the epsilon value used for the test

is.surrogate

logical, TRUE if test indicates S is a good surrogate, FALSE otherwise

Author(s)

Layla Parast

Examples

data(example.data)
test.surrogate(yone = example.data$y1, yzero = example.data$y0, sone = example.data$s1, 
szero = example.data$s0)