fmecTest: Odds Ratio/Difference Non-inferiority tests In nivm: Noninferiority Tests with Variable Margins

Description

Rohmel and Keier (2013) developed these non-inferioirty tests with variable margins. One margin function, NiM3, has the variable margin measuring a constant difference in proportions (0.10 in paper) after a threshold (0.20 proportion in the control group), or tests for differences defined in terms of a constant odds ratio (1.71 in paper) at values less than the threshold. The fmecTest with type='max' gives the maximum of two p-values, either a difference in proportions test (one-sided asymptotic method of Farrington and Manning, 1990) or an odds ratio test (one-sided Fisher's exact). This test is NiM3/T2 in Rohmel and Keier (2013). We also provide an exact version of this test with fmecExact, denoted NiM3/T3 in Rohmel and Keier (2013). When type='switch' the tests are like T1 of Rohmel and Keier (2013).

Usage

 1 2 3 4 5 6 7 fmecTest(x1, n1, x2, n2, threshold = 0.2, delta = 0.1, alternative = c("less","greater"), type = c("max", "switch")) fmecExact(x1, n1, x2, n2, threshold = 0.2, delta = 0.1, alternative = c("less", "greater"), type = c("max", "switch"), ngrid = 1000)

Arguments

 x1 number of failures in control group n1 number of individuals in control group x2 number of failures in test group n2 number of individuals in test group threshold threshold on proportion in control group: above it use constant difference margin, below it use difference margin with constant odds ratio delta difference margin at threshold alternative must be 'less'. the value 'greater' is not supported at this time. type either 'max' (maximum of Fisher's exact p-value or Farrington and Manning p-value) or 'switch' (Fisher's exact p-value below threhold and Farington and Manning p-value above threhold). ngrid grid size for the search for the maximum p-value. Search over the control proportion values 0:ngrid/ngrid.

Details

For details see Rohmel and Keier (2013, Section 3). These functions only use NiM3.

Value

a list of class 'htest':

 statistic the threshold, delta (difference margin at threshold), and odds ratio at threshold data.name gives x1,x2,n1,n2 as a character string method description of test p.value one-sided p-value null.value delta, the difference margin at threshold alternative direction of alternative hypothesis

Michael P. Fay

References

Farrington, CP and Manning G (1990). "Test statistics and sample size formulae for comparative binomial trials with null hypothesis of non-zero risk difference or non-unit relative risk" Statistics in Medicine 9:1447-1454.

Rohmel, J, and Kieser, M (2013). "Investigations on non-inferiority - - the Food and Drug Administration draft guidance on treatments for nosocomial pneumonia as a case for exact tests for binomial proportions" Statistics in Medicine 32:2335-2348.

Examples

 1 2 fmecTest(6,10,2,12,alternative="less",type="max") fmecExact(6,10,2,12,alternative="less",type="max")

Example output

Odds Ratio/Difference Test type=max

data:  x1=6 n1=10 x2=2 n2=12
threshold = 0.2000, difference = 0.1000, odds ratio = 1.7143, p-value =
0.01064
alternative hypothesis: true difference in proportions is less than 0.1

Exact Odds Ratio/Difference Test type=max

data:  x1=6 n1=10 x2=2 n2=12
threshold = 0.2000, difference = 0.1000, odds ratio = 1.7143, p-value =
0.008839
alternative hypothesis: true difference in proportions is less than 0.1

nivm documentation built on May 2, 2019, 8:22 a.m.