Package 'mfx'

Title: Marginal Effects, Odds Ratios and Incidence Rate Ratios for GLMs
Description: Estimates probit, logit, Poisson, negative binomial, and beta regression models, returning their marginal effects, odds ratios, or incidence rate ratios as an output. Greene (2008, pp. 780-7) provides a textbook introduction to this topic.
Authors: Alan Fernihough [aut, cre], Arne Henningsen [ctb]
Maintainer: Alan Fernihough <[email protected]>
License: GPL-2 | GPL-3
Version: 1.2-2
Built: 2024-10-26 06:26:19 UTC
Source: CRAN

Help Index


Marginal effects for a beta regression.

Description

This function estimates a beta regression model and calculates the corresponding marginal effects.

Usage

betamfx(formula, data, atmean = TRUE, robust = FALSE, 
        clustervar1 = NULL, clustervar2 = NULL, 
        control = betareg.control(), link.phi = NULL, type = "ML")

Arguments

formula

an object of class “formula” (or one that can be coerced to that class).

data

the data frame containing these data. This argument must be used.

atmean

default marginal effects represent the partial effects for the average observation. If atmean = FALSE the function calculates average partial effects.

robust

if TRUE the function reports White/robust standard errors.

clustervar1

a character value naming the first cluster on which to adjust the standard errors.

clustervar2

a character value naming the second cluster on which to adjust the standard errors for two-way clustering.

control

a list of control arguments specified via betareg.control.

link.phi

as in the betareg function.

type

as in the betareg function.

Details

The underlying link function in the mean model (mu) is “logit”. If both robust=TRUE and !is.null(clustervar1) the function overrides the robust command and computes clustered standard errors.

Value

mfxest

a coefficient matrix with columns containing the estimates, associated standard errors, test statistics and p-values.

fit

the fitted betareg object.

dcvar

a character vector containing the variable names where the marginal effect refers to the impact of a discrete change on the outcome. For example, a factor variable.

call

the matched call.

References

Francisco Cribari-Neto, Achim Zeileis (2010). Beta Regression in R. Journal of Statistical Software 34(2), 1-24.

Bettina Gruen, Ioannis Kosmidis, Achim Zeileis (2012). Extended Beta Regression in R: Shaken, Stirred, Mixed, and Partitioned. Journal of Statistical Software, 48(11), 1-25.

See Also

betaor, betareg

Examples

# simulate some data
set.seed(12345)
n = 1000
x = rnorm(n)

# beta outcome
y = rbeta(n, shape1 = plogis(1 + 0.5 * x), shape2 = (abs(0.2*x)))
# use Smithson and Verkuilen correction
y = (y*(n-1)+0.5)/n

data = data.frame(y,x)
betamfx(y~x|x, data=data)

Odds ratios for a beta regression.

Description

This function estimates a beta regression model and calculates the corresponding odds ratios.

Usage

betaor(formula, data, robust = FALSE, clustervar1 = NULL, clustervar2 = NULL, 
       control = betareg.control(), link.phi = NULL, type = "ML")

Arguments

formula

an object of class “formula” (or one that can be coerced to that class).

data

the data frame containing these data. This argument must be used.

robust

if TRUE the function reports White/robust standard errors.

clustervar1

a character value naming the first cluster on which to adjust the standard errors.

clustervar2

a character value naming the second cluster on which to adjust the standard errors for two-way clustering.

control

a list of control arguments specified via betareg.control.

link.phi

as in the betareg function.

type

as in the betareg function.

Details

The underlying link function in the mean model (mu) is "logit". If both robust=TRUE and !is.null(clustervar1) the function overrides the robust command and computes clustered standard errors.

Value

oddsratio

a coefficient matrix with columns containing the estimates, associated standard errors, test statistics and p-values.

fit

the fitted betareg object.

call

the matched call.

References

Francisco Cribari-Neto, Achim Zeileis (2010). Beta Regression in R. Journal of Statistical Software 34(2), 1-24.

Bettina Gruen, Ioannis Kosmidis, Achim Zeileis (2012). Extended Beta Regression in R: Shaken, Stirred, Mixed, and Partitioned. Journal of Statistical Software, 48(11), 1-25.

See Also

betamfx, betareg

Examples

# simulate some data
set.seed(12345)
n = 1000
x = rnorm(n)

# beta outcome
y = rbeta(n, shape1 = plogis(1 + 0.5 * x), shape2 = (abs(0.2*x)))
# use Smithson and Verkuilen correction
y = (y*(n-1)+0.5)/n

data = data.frame(y,x)
betaor(y~x|x, data=data)

Marginal effects for a logit regression.

Description

This function estimates a binary logistic regression model and calculates the corresponding marginal effects.

Usage

logitmfx(formula, data, atmean = TRUE, robust = FALSE, clustervar1 = NULL, 
         clustervar2 = NULL, start = NULL, control = list())

Arguments

formula

an object of class “formula” (or one that can be coerced to that class).

data

the data frame containing these data. This argument must be used.

atmean

default marginal effects represent the partial effects for the average observation. If atmean = FALSE the function calculates average partial effects.

robust

if TRUE the function reports White/robust standard errors.

clustervar1

a character value naming the first cluster on which to adjust the standard errors.

clustervar2

a character value naming the second cluster on which to adjust the standard errors for two-way clustering.

start

starting values for the parameters in the glm model.

control

see glm.control.

Details

If both robust=TRUE and !is.null(clustervar1) the function overrides the robust command and computes clustered standard errors.

Value

mfxest

a coefficient matrix with columns containing the estimates, associated standard errors, test statistics and p-values.

fit

the fitted glm object.

dcvar

a character vector containing the variable names where the marginal effect refers to the impact of a discrete change on the outcome. For example, a factor variable.

call

the matched call.

References

William H. Greene (2008). Econometric Analysis (6th ed.). Prentice Hall, N.Y. pp 770-787.

See Also

logitor, glm

Examples

# simulate some data
set.seed(12345)
n = 1000
x = rnorm(n)

# binary outcome
y = ifelse(pnorm(1 + 0.5*x + rnorm(n))>0.5, 1, 0)

data = data.frame(y,x)
logitmfx(formula=y~x, data=data)

Odds ratios for a logit regression.

Description

This function estimates a binary logistic regression model and calculates the corresponding odds ratios.

Usage

logitor(formula, data, robust = FALSE, clustervar1 = NULL, clustervar2 = NULL, 
        start = NULL, control = list())

Arguments

formula

an object of class “formula” (or one that can be coerced to that class).

data

the data frame containing these data. This argument must be used.

robust

if TRUE the function reports White/robust standard errors.

clustervar1

a character value naming the first cluster on which to adjust the standard errors.

clustervar2

a character value naming the second cluster on which to adjust the standard errors for two-way clustering.

start

starting values for the parameters in the glm model.

control

see glm.control.

Details

If both robust=TRUE and !is.null(clustervar1) the function overrides the robust command and computes clustered standard errors.

Value

oddsratio

a coefficient matrix with columns containing the estimates, associated standard errors, test statistics and p-values.

fit

the fitted glm object.

call

the matched call.

See Also

logitmfx, glm

Examples

# simulate some data
set.seed(12345)
n = 1000
x = rnorm(n)

# binary outcome
y = ifelse(pnorm(1 + 0.5*x + rnorm(n))>0.5, 1, 0)

data = data.frame(y,x)
logitor(formula=y~x, data=data)

Incidence rate ratios for a negative binomial regression.

Description

This function estimates a negative binomial regression model and calculates the corresponding incidence rate ratios.

Usage

negbinirr(formula, data, robust = FALSE, clustervar1 = NULL, 
          clustervar2 = NULL, start = NULL, control = glm.control())

Arguments

formula

an object of class “formula” (or one that can be coerced to that class).

data

the data frame containing these data. This argument must be used.

robust

if TRUE the function reports White/robust standard errors.

clustervar1

a character value naming the first cluster on which to adjust the standard errors.

clustervar2

a character value naming the second cluster on which to adjust the standard errors for two-way clustering.

start

starting values for the parameters in the glm.nb model.

control

see glm.control.

Details

If both robust=TRUE and !is.null(clustervar1) the function overrides the robust command and computes clustered standard errors.

Value

irr

a coefficient matrix with columns containing the estimates, associated standard errors, test statistics and p-values.

fit

the fitted glm.nb object.

call

the matched call.

See Also

negbinmfx, glm.nb

Examples

# simulate some data
set.seed(12345)
n = 1000
x = rnorm(n)
y = rnegbin(n, mu = exp(1 + 0.5 * x), theta = 0.5)

data = data.frame(y,x)

negbinirr(formula=y~x,data=data)

Marginal effects for a negative binomial regression.

Description

This function estimates a negative binomial regression model and calculates the corresponding marginal effects.

Usage

negbinmfx(formula, data, atmean = TRUE, robust = FALSE, clustervar1 = NULL, 
          clustervar2 = NULL, start = NULL, control = glm.control())

Arguments

formula

an object of class “formula” (or one that can be coerced to that class).

data

the data frame containing these data. This argument must be used.

atmean

default marginal effects represent the partial effects for the average observation. If atmean = FALSE the function calculates average partial effects.

robust

if TRUE the function reports White/robust standard errors.

clustervar1

a character value naming the first cluster on which to adjust the standard errors.

clustervar2

a character value naming the second cluster on which to adjust the standard errors for two-way clustering.

start

starting values for the parameters in the glm.nb model.

control

see glm.control.

Details

If both robust=TRUE and !is.null(clustervar1) the function overrides the robust command and computes clustered standard errors.

Value

mfxest

a coefficient matrix with columns containing the estimates, associated standard errors, test statistics and p-values.

fit

the fitted glm.nb object.

dcvar

a character vector containing the variable names where the marginal effect refers to the impact of a discrete change on the outcome. For example, a factor variable.

call

the matched call.

See Also

negbinirr, glm.nb

Examples

# simulate some data
set.seed(12345)
n = 1000
x = rnorm(n)
y = rnegbin(n, mu = exp(1 + 0.5 * x), theta = 0.5)

data = data.frame(y,x)

negbinmfx(formula=y~x,data=data)

Incidence rate ratios for a Poisson regression.

Description

This function estimates a negative binomial regression model and calculates the corresponding incidence rate ratios.

Usage

poissonirr(formula, data, robust = FALSE, clustervar1 = NULL, 
           clustervar2 = NULL, start = NULL, control = list())

Arguments

formula

an object of class “formula” (or one that can be coerced to that class).

data

the data frame containing these data. This argument must be used.

robust

if TRUE the function reports White/robust standard errors.

clustervar1

a character value naming the first cluster on which to adjust the standard errors.

clustervar2

a character value naming the second cluster on which to adjust the standard errors for two-way clustering.

start

starting values for the parameters in the glm model.

control

see glm.control.

Details

If both robust=TRUE and !is.null(clustervar1) the function overrides the robust command and computes clustered standard errors.

Value

irr

a coefficient matrix with columns containing the estimates, associated standard errors, test statistics and p-values.

fit

the fitted glm object.

call

the matched call.

See Also

poissonmfx, glm

Examples

# simulate some data
set.seed(12345)
n = 1000
x = rnorm(n)
y = rnegbin(n, mu = exp(1 + 0.5 * x), theta = 0.5)

data = data.frame(y,x)

poissonirr(formula=y~x,data=data)

Marginal effects for a Poisson regression.

Description

This function estimates a Poisson regression model and calculates the corresponding marginal effects.

Usage

poissonmfx(formula, data, atmean = TRUE, robust = FALSE, clustervar1 = NULL, 
           clustervar2 = NULL, start = NULL, control = list())

Arguments

formula

an object of class “formula” (or one that can be coerced to that class).

data

the data frame containing these data. This argument must be used.

atmean

default marginal effects represent the partial effects for the average observation. If atmean = FALSE the function calculates average partial effects.

robust

if TRUE the function reports White/robust standard errors.

clustervar1

a character value naming the first cluster on which to adjust the standard errors.

clustervar2

a character value naming the second cluster on which to adjust the standard errors for two-way clustering.

start

starting values for the parameters in the glm model.

control

see glm.control.

Details

If both robust=TRUE and !is.null(clustervar1) the function overrides the robust command and computes clustered standard errors.

Value

mfxest

a coefficient matrix with columns containing the estimates, associated standard errors, test statistics and p-values.

fit

the fitted glm object.

dcvar

a character vector containing the variable names where the marginal effect refers to the impact of a discrete change on the outcome. For example, a factor variable.

call

the matched call.

See Also

poissonirr, glm

Examples

# simulate some data
set.seed(12345)
n = 1000
x = rnorm(n)
y = rnegbin(n, mu = exp(1 + 0.5 * x), theta = 0.5)

data = data.frame(y,x)

poissonmfx(formula=y~x,data=data)

Marginal effects for a probit regression.

Description

This function estimates a probit regression model and calculates the corresponding marginal effects.

Usage

probitmfx(formula, data, atmean = TRUE, robust = FALSE, clustervar1 = NULL, 
          clustervar2 = NULL, start = NULL, control = list())

Arguments

formula

an object of class “formula” (or one that can be coerced to that class).

data

the data frame containing these data. This argument must be used.

atmean

default marginal effects represent the partial effects for the average observation. If atmean = FALSE the function calculates average partial effects.

robust

if TRUE the function reports White/robust standard errors.

clustervar1

a character value naming the first cluster on which to adjust the standard errors.

clustervar2

a character value naming the second cluster on which to adjust the standard errors for two-way clustering.

start

starting values for the parameters in the glm model.

control

see glm.control.

Details

If both robust=TRUE and !is.null(clustervar1) the function overrides the robust command and computes clustered standard errors.

Value

mfxest

a coefficient matrix with columns containing the estimates, associated standard errors, test statistics and p-values.

fit

the fitted glm object.

dcvar

a character vector containing the variable names where the marginal effect refers to the impact of a discrete change on the outcome. For example, a factor variable.

call

the matched call.

References

William H. Greene (2008). Econometric Analysis (6th ed.). Prentice Hall, N.Y. pp 770-787.

See Also

glm

Examples

# simulate some data
set.seed(12345)
n = 1000
x = rnorm(n)

# binary outcome
y = ifelse(pnorm(1 + 0.5*x + rnorm(n))>0.5, 1, 0)

data = data.frame(y,x)
probitmfx(formula=y~x, data=data)