createTestData {SPCDAnalyze}

Creates a test data set for the example

Description

Helper function for example that creates a test data set in the proper format

Usage

createTestData(times = c(0:11), transition = 5, rx1 = 0.5, rx2 = 1, slope = 0.5,
error=0.3, n = c(50, 50, 50))

Arguments

times

Observation times

transition

Time where phase I ends and Phase II begins

rx1

Drug effect on slope of outcome during phase 1.

rx2

Drug effect on slope of outcome during phase 2.

slope

Slope of outcome.

error

Standard Deviation of the error.

n

Sample sizes of the three groups, Placebo-Placebo, Placebo-Drug, Drug

Details

The model used is that the outcome is equal to (slope) times times for patients in the Placebo cohort with the addition of rx1 for the Drug cohort, during the first phase, and is equal to (slope+rx2) times (times-transition) for the Drug group in the second phase, and slope for the Placebo group in the second phase. A random noise is added to each observation with standard deviation error

Value

A dataframe is returned with variables:

ID

Patient ID

rx

Integer 1,2,3 indicating whether the patient is in the placebo-placebo, placebo-drug or drug groups

transition

Time that phase 1 ends and phase 2 starts

time

The observation time

y

The value of the outcome variable

Author(s)

David A. Schoenfeld

References

Fava, M., Evins, A. E., Dorer, D. J., and Schoenfeld, D. A. (2003). The problem of the placebo response in clinical trials for psychiatric disorders: culprits, possible remedies, and a novel study design approach. Psychotherapy and Psychosomatics, 72,3, 115–127.

Chen, Y. F., Yang, Y., Hung, H. J., & Wang, S. J. (2011). Evaluation of performance of some enrichment designs dealing with high placebo response in psychiatric clinical trials. Contemporary clinical trials, 32,4, 592-604.

Examples

createTestData(times=0:3,n=c(3,3,3),transition=5,rx1=0,rx2=0)