empBayes: empBayes

In rnorberg/bastudy: A Package for Before and After Traffic Studies

Description

Calculates Crash Modification Factor (CMF) for a before/after traffic study using Empirical Bayes to avoid regression to the mean (RTM)

Usage

empBayes(reference, before, after, depVar, offsetVar = NULL,
  indepVars = setdiff(names(reference), c(depVar, offsetVar)),
  forceKeep = NULL, alpha = 0.95)

Arguments

reference	Reference data
before	Treatment data, before some change was made
after	Treatment data, after some change was made
depVar	The dependent variable (the number of crashes - should always be of class integer or numeric).
offsetVar	An offset variable (eg years)
indepVars	Variables used to model the outcome variable depVar
forceKeep	A character vector of variable names. These variables will not be considered for removal during the variable selection process.
alpha	Level of confidence

Details

None at this time

Value

Returns a list object containing the CMF, its variance, standard error, and 1-alpha/2 CI

Author(s)

Jung-han Wang and Robert Norberg

Examples

data(Reference)
data(Before)
data(After)
empBayes(reference = Reference, before = Before, after = After,
 depVar = "kabco", offsetVar = "year")

rnorberg/bastudy documentation built on May 27, 2019, 9:57 a.m.