TrendInTrend (version 1.1.2)

ttdetect: 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

An object 'ttdetect' is a list of containing the following components:

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

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References

Ertefaie, A., Small, D. S., Ji, X., Leonard, C., & Hennessy, S. (2018) Statistical Power for Trend-in-trend Design. Epidemiology (Cambridge, Mass.), 29(3), 21-23.

Examples

# NOT RUN {
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))
  
# }
# NOT RUN {
   
# }