ttdetect {TrendInTrend}

Finding a detectable odds Ratio with a given power

Description

Monte Carlo power calculation for a trend-in-trend design.

Usage

ttdetect(N, time, G, cstat, alpha_t, beta_0, power, nrep, OR.vec)

Arguments

N

Sample Size.

time

Number of time points.

G

Number of CPE strata.

cstat

Value of the c-statistic.

alpha_t

A scaler that qunatifies the trend in exposure prevalence.

beta_0

Intercept of the outcome model.

power

A given power.

nrep

Number of Monte Carlo replicates.

OR.vec

A vector of odds Ratios.

Value

Power

A vector of calculated powers for a given OR.vec

OR.vec

A vector of odds Ratios

DetectDifference

A detectable difference for a given power value

References

Ertefaie, A., Small, D., Ji, X., Leonard, C., Hennessy, S. (2018). Statistical Power for Trend-in-trend Design. Epidemiology 29(3), e21.

Examples

set.seed(123)
ttdetect(N=10000,time=10,G=10,cstat=0.75,alpha_t= 0.4,beta_0=-4.3,
        power=0.80,nrep=50, OR.vec=c(1.9,2.0,2.1,2.2))