dsrTest: Tests and Confidence Intervals on Directly Standardized Rates

In mnel/dsrTest: Tests and Confidence Intervals on Directly Standardized Rates for Several Methods

Description

A number of methods have been proposed for calculating confidence intervals for directly standardized rates. Ng et al (2008), compare a number of methods, some of which are implemented here. The default uses the Gamma method by Fay and Feuer (1997) and implemented in wspoissonTest.

Usage

dsrTest(x, n, w, null.value = NULL, alternative = c("two.sided", "less",
  "greater"), conf.level = 0.95, mult = 1, method = c("gamma",
  "asymptotic", "dobson", "beta", "bootstrap"), control = list())

Arguments

x	a vector of strata-specific counts.
n	a vector of strata-specific time bases for counts.
w	a vector of strata-specific weights (or standard populations).
null.value	a null hypothesis value of the directly rate, if NULL no test is done. If not NULL, provide in rate per mult.
alternative	type of alternative hypothesis.
conf.level	confidence level for the returned confidence interval.
mult	a factor to multiply the estimate and confidence intervals by, to give rates per mult.
method	Method used to perform the test and construct the confidence interval. See details.
control	list of arguments / type of modification used for each method. See details and relevant "xxxxControl" documentation

Details

Five classes of method have been implemented here:

"gamma"

Calls wspoissonTest. By default uses the Gamma Method proposed by Fay and Feuer (1997). Modifications proposed by Tiwari et al (2006) and Fay and Kim (2017) also implemented - see gammaControl.

"asymptotic"

Using the normal approximation of the MLE or transformed MLE distribution - see asymptoticControl

"dobson"

Uses the method proposed by Dobson et al (1991). Estimating the confidence interval on the unweighted sum is done by calling poisson.exact - both the exact method and a mid-p method are possible - see dobsonControl.

"beta"

Methods based on the beta distribution by Tiwari et al (2006) - see betaControl.

"bootstrap"

Approximate Bootstrap method by Swift (1995). P-values are estimated by solving for p.

For each method there is a control function that will return a list of parameters that can be used to define sub-types of each of the broad groups

Value

a list with class "htest" containing the following components:

statistic	number of strata or summands: k = length(x)
parameter	mult
p.value	p-value, set to NA if null.value = NULL
conf.int	confidence interval on the true directly standardized rate
estimate	directly standardized rate
null.value	null hypothesis value for the DSR
alternative	alternative hypothesis type
method	description of the method
data.name	description of the data

References

Dobson, AJ, Kuulasmaa, K, Eberle, E and Scherer, J (1991) 'Confidence intervals for weighted sums of Poisson parameters', Statistics in Medicine, 10: 457–462. doi: 10.1002/sim.4780100317

Swift, MB (1995). 'Simple confidence intervals for standardized rates based on the approximate bootstrap method', Statistics in Medicine, 14, 1875–1888. doi: 10.1002/sim.4780141704.

Fay MP & Feuer EJ (1997). 'Confidence intervals for directly standardized rates: a method based on the gamma distribution. Statistics in Medicine*. 16: 791–801. https://doi.org/10.1002/(SICI)1097-0258(19970415)16:7<791::AID-SIM500>3.0.CO;2-%23

Tiwari RC, Clegg LX, & Zou Z (2006). 'Efficient interval estimation for age-adjusted cancer rates.' Statistical Methods in Medical Research 15: 547–569. doi: 10.1177/0962280206070621

Ng HKT, Filardo, G & Zheng G (2008). 'Confidence interval estimating procedures for standardized incidence rates.' Computational Statistics and Data Analysis 52 3501–3516. doi: 10.1016/j.csda.2007.11.004

See Also

wspoissonTest, poisson.exact, gammaControl, dobsonControl, asymptoticControl, betaControl

mnel/dsrTest documentation built on May 23, 2019, 5:06 a.m.