Package 'cquad'

Title: Conditional Maximum Likelihood for Quadratic Exponential Models for Binary Panel Data
Description: Estimation, based on conditional maximum likelihood, of the quadratic exponential model proposed by Bartolucci, F. & Nigro, V. (2010, Econometrica) <DOI:10.3982/ECTA7531> and of a simplified and a modified version of this model. The quadratic exponential model is suitable for the analysis of binary longitudinal data when state dependence (further to the effect of the covariates and a time-fixed individual intercept) has to be taken into account. Therefore, this is an alternative to the dynamic logit model having the advantage of easily allowing conditional inference in order to eliminate the individual intercepts and then getting consistent estimates of the parameters of main interest (for the covariates and the lagged response). The simplified version of this model does not distinguish, as the original model does, between the last time occasion and the previous occasions. The modified version formulates in a different way the interaction terms and it may be used to test in a easy way state dependence as shown in Bartolucci, F., Nigro, V. & Pigini, C. (2018, Econometric Reviews) <DOI:10.1080/07474938.2015.1060039>. The package also includes estimation of the dynamic logit model by a pseudo conditional estimator based on the quadratic exponential model, as proposed by Bartolucci, F. & Nigro, V. (2012, Journal of Econometrics) <DOI:10.1016/j.jeconom.2012.03.004>. For large time dimensions of the panel, the computation of the proposed models involves a recursive function from Krailo M. D., & Pike M. C. (1984, Journal of the Royal Statistical Society. Series C (Applied Statistics)) and Bartolucci F., Valentini, F. & Pigini C. (2021, Computational Economics <DOI:10.1007/s10614-021-10218-2>.
Authors: Francesco Bartolucci (University of Perugia), Claudia Pigini (University of Ancona "Politecnica delle Marche"), Francesco Valentini (University of Ancona "Politecnica delle Marche")
Maintainer: Francesco Bartolucci <[email protected]>
License: GPL (>= 2)
Version: 2.3
Built: 2024-10-16 05:17:02 UTC
Source: https://github.com/fravale/cquad_dev

Help Index


Conditional Maximum Likelihood for Quadratic Exponential Models for Binary Panel Data

Description

Estimation, based on conditional maximum likelihood, of the quadratic exponential model proposed by Bartolucci & Nigro (2010) and of a simplified and a modified version of this model. The quadratic exponential model is suitable for the analysis of binary longitudinal data when state dependence (further to the effect of the covariates and a time-fixed individual intercept) has to be taken into account. Therefore, this is an alternative to the dynamic logit model having the advantage of easily allowing conditional inference in order to eliminate the individual intercepts and then getting consistent estimates of the parameters of main interest (for the covariates and the lagged response). The simplified version of this model does not distinguish, as the original model does, between the last time occasion and the previous occasions. The modified version formulates in a different way the interaction terms and it may be used to test in a easy way state dependence as shown in Bartolucci, Nigro & Pigini (2018). The package also includes estimation of the dynamic logit model by a pseudo conditional estimator based on the quadratic exponential model, as proposed by Bartolucci & Nigro (2012).

Author(s)

Francesco Bartolucci (University of Perugia, IT), Claudia Pigini (University of Perugia, IT), Francesco Valentini (University of Ancona "Politecnica delle Marche")

Maintainer: Francesco Bartolucci <[email protected]>

References

Bartolucci, F. and Nigro, V. (2010), A dynamic model for binary panel data with unobserved heterogeneity admitting a root-n consistent conditional estimator, Econometrica, 78, 719-733.

Bartolucci, F. and Nigro, V. (2012). Pseudo conditional maximum likelihood estimation of the dynamic logit model for binary panel data, Journal of Econometrics, 170, 102-116.

Bartolucci, F. and Pigini, C. (2017). cquad: An R and Stata package for conditional maximum likelihood estimation of dynamic binary panel data models, Journal of Statistical Software, 78, 1-26, doi:10.18637/jss.v078.i07.

Bartolucci, F., Nigro, V., & Pigini, C. (2018). Testing for state dependence in binary panel data with individual covariates by a modified quadratic exponential model. Econometric Reviews, 37(1), 61-88.

Bartolucci, F., Valentini. F., & Pigini, C. (2021), Recursive Computation of the Conditional Probability Function of the Quadratic Exponential Model for Binary Panel Data, Computational Economics, https://doi.org/10.1007/s10614-021-10218-2.

Cox, D. R. (1972), The Analysis of multivariate binary data, Applied Statistics, 21, 113-120.

Examples

# example based on simulated data
data(data_sim)
data_sim = data_sim[1:500,]   # to speed up the example, remove otherwise
# static model
out1 = cquad(y~X1+X2,data_sim)
# dynamic model
out2 = cquad(y~X1+X2,data_sim,dyn=TRUE)

Interface for functions fitting different versions of cquad

Description

Fit by conditional maximum likelihood each of the models in cquad package.

Usage

cquad(formula, data, index = NULL, model = c("basic","equal","extended","pseudo"),
             w = rep(1, n), dyn = FALSE, Ttol=10)

Arguments

formula

formula with the same syntax as in plm package

data

data.frame or pdata.frame

index

to denote panel structure as in plm package

model

type of model = "basic", "equal", "extended", "pseudo"

w

vector of weights (optional)

dyn

TRUE if in the dynamic version; FALSE for the static version (by default)

Ttol

Threshold individual observations that activates the recursive algorithm (default=10)

Value

formula

formula defining the model

lk

conditional log-likelihood value

coefficients

estimate of the regression parameters

vcov

asymptotic variance-covariance matrix for the parameter estimates

scv

matrix of individual scores

J

Hessian of the log-likelihood function

se

standard errors

ser

robust standard errors

Tv

number of time occasions for each unit

Author(s)

Francesco Bartolucci (University of Perugia), Claudia Pigini (University of Ancona "Politecnica delle Marche"), Francesco Valentini (University of Ancona "Politecnica delle Marche")

Examples

# example based on simulated data
data(data_sim)
data_sim = data_sim[1:500,]   # to speed up the example, remove otherwise
# basic (static) model
out1 = cquad(y~X1+X2,data_sim)
summary(out1)
# basic (dynamic) model
out2 = cquad(y~X1+X2,data_sim,dyn=TRUE)
summary(out2)
# equal model
out3 = cquad(y~X1+X2,data_sim,model="equal")
summary(out3)
# extended model
out4 = cquad(y~X1+X2,data_sim,model="extended")
summary(out4)
# psuedo CML for dynamic model
out5 = cquad(y~X1+X2,data_sim,model="pseudo")
summary(out5)

Conditional maximum likelihood estimation of the basic quadratic exponential model

Description

Fit by conditional maximum likelihood a simplified version of the model for binary longitudinal data proposed by Bartolucci & Nigro (2010); see also Cox (1972).

Usage

cquad_basic(id, yv, X = NULL, be = NULL, w = rep(1, n), dyn =
FALSE, Ttol=10)

Arguments

id

list of the reference unit of each observation

yv

corresponding vector of response variables

X

corresponding matrix of covariates (optional)

be

initial vector of parameters (optional)

w

vector of weights (optional)

dyn

TRUE if in the dynamic version; FALSE for the static version (by default)

Ttol

Threshold individual observations that activates the recursive algorithm (default=10)

Value

formula

formula defining the model

lk

conditional log-likelihood value

coefficients

estimate of the regression parameters (including for the lag-response)

vcov

asymptotic variance-covariance matrix for the parameter estimates

scv

matrix of individual scores

J

Hessian of the log-likelihood function

se

standard errors

ser

robust standard errors

Tv

number of time occasions for each unit

Author(s)

Francesco Bartolucci (University of Perugia), Claudia Pigini (University of Ancona "Politecnica delle Marche"), Francesco Valentini (University of Ancona "Politecnica delle Marche")

References

Bartolucci, F. and Nigro, V. (2010), A dynamic model for binary panel data with unobserved heterogeneity admitting a root-n consistent conditional estimator, Econometrica, 78, pp. 719-733.

Cox, D. R. (1972), The Analysis of multivariate binary data, Applied Statistics, 21, 113-120.

Examples

# example based on simulated data
data(data_sim)
data_sim = data_sim[1:500,]   # to speed up the example, remove otherwise
id = data_sim$id; yv = data_sim$y; X = cbind(X1=data_sim$X1,X2=data_sim$X2)
# static model
out1 = cquad_basic(id,yv,X,Ttol=10)
summary(out1)
# dynamic model
out2 = cquad_basic(id,yv,X,dyn=TRUE,Ttol=10)
summary(out2)

Conditional maximum likelihood estimation for the modified version of the quadratic exponential model (to test for state dependence)

Description

Fit by conditional maximum likelihood a modified version of the model for binary longitudinal data proposed by Bartolucci & Nigro (2010), in which the interaction terms have an extended form. This modified version is used to test for state dependence as described in Bartolucci et al. (2018).

Usage

cquad_equ(id, yv, X = NULL, be = NULL, w = rep(1, n), Ttol=10)

Arguments

id

list of the reference unit of each observation

yv

corresponding vector of response variables

X

corresponding matrix of covariates (optional)

be

initial vector of parameters (optional)

w

vector of weights (optional)

Ttol

Threshold individual observations that activates the recursive algorithm (default=10)

Value

formula

formula defining the model

lk

conditional log-likelihood value

coefficients

estimate of the regression parameters (including for the lag-response)

vcov

asymptotic variance-covariance matrix for the parameter estimates

scv

matrix of individual scores

J

Hessian of the log-likelihood function

se

standard errors

ser

robust standard errors

Tv

number of time occasions for each unit

Author(s)

Francesco Bartolucci (University of Perugia), Claudia Pigini (University of Perugia), Francesco Valentini (University of Ancona "Politecnica delle Marche")

References

Bartolucci, F. and Nigro, V. (2010), A dynamic model for binary panel data with unobserved heterogeneity admitting a root-n consistent conditional estimator, Econometrica, 78, 719-733.

Bartolucci, F., Nigro, V., & Pigini, C. (2018). Testing for state dependence in binary panel data with individual covariates by a modified quadratic exponential model. Econometric Reviews, 37(1), 61-88.

Examples

# example based on simulated data
data(data_sim)
data_sim = data_sim[1:500,]   # to speed up the example, remove otherwise
id = data_sim$id; yv = data_sim$y; X = cbind(X1=data_sim$X1,X2=data_sim$X2)

out = cquad_equ(id,yv,X,Ttol=10)

Conditional maximum likelihood estimation of the quadratic exponential model for panel data

Description

Fit by conditional maximum likelihood the model for binary longitudinal data proposed by Bartolucci & Nigro (2010).

Usage

cquad_ext(id, yv, X = NULL, be = NULL, w = rep(1, n),Ttol=10)

Arguments

id

list of the reference unit of each observation

yv

corresponding vector of response variables

X

corresponding matrix of covariates (optional)

be

initial vector of parameters (optional)

w

vector of weights (optional)

Ttol

Threshold individual observations that activates the recursive algorithm (default=10)

Value

formula

formula defining the model

lk

conditional log-likelihood value

coefficients

estimate of the regression parameters (including for the lag-response)

vcov

asymptotic variance-covariance matrix for the parameter estimates

scv

matrix of individual scores

J

Hessian of the log-likelihood function

se

standard errors

ser

robust standard errors

Tv

number of time occasions for each unit

Author(s)

Francesco Bartolucci (University of Perugia), Claudia Pigini (University of Ancona "Politecnica delle Marche"), Francesco Valentini (University of Ancona "Politecnica delle Marche")

References

Bartolucci, F. and Nigro, V. (2010), A dynamic model for binary panel data with unobserved heterogeneity admitting a root-n consistent conditional estimator. Econometrica, 78, pp. 719-733.

Examples

# example based on simulated data
data(data_sim)
data_sim = data_sim[1:500,]   # to speed up the example, remove otherwise
id = data_sim$id; yv = data_sim$y; X = cbind(X1=data_sim$X1,X2=data_sim$X2)
# static model
out = cquad_ext(id,yv,X,Ttol=10)
summary(out)

Pseudo conditional maximum likelihood estimation of the dynamic logit model

Description

Estimate the dynamic logit model for binary longitudinal data by the pseudo conditional maximum likelihood method proposed by Bartolucci & Nigro (2012).

Usage

cquad_pseudo(id, yv, X = NULL, be = NULL, w = rep(1,n), Ttol=10)

Arguments

id

list of the reference unit of each observation

yv

corresponding vector of response variables

X

corresponding matrix of covariates (optional)

be

initial vector of parameters (optional)

w

vector of weights (optional)

Ttol

Threshold individual observations that activates the recursive algorithm (default=10)

Value

formula

formula defining the model

lk

conditional log-likelihood value

coefficients

estimate of the regression parameters (including for the lag-response)

vcov

asymptotic variance-covariance matrix for the parameter estimates

scv

matrix of individual scores

J

Hessian of the log-likelihood function

se

standard errors

se2

robust standard errors that also take into account the first step

Tv

number of time occasions for each unit

Author(s)

Francesco Bartolucci (University of Perugia), Claudia Pigini (University of Ancona "Politecnica delle Marche"), Francesco Valentini (University of Ancona "Politecnica delle Marche")

References

Bartolucci, F. and Nigro, V. (2010), A dynamic model for binary panel data with unobserved heterogeneity admitting a root-n consistent conditional estimator, Econometrica, 78, 719-733.

Bartolucci, F. and Nigro, V. (2012), Pseudo conditional maximum likelihood estimation of the dynamic logit model for binary panel data, Journal of Econometrics, 170, 102-116.

Examples

## Not run: 
# example based on simulated data
data(data_sim)
data_sim = data_sim[1:500,]   # to speed up the example, remove otherwise
id = data_sim$id; yv = data_sim$y; X = cbind(X1=data_sim$X1,X2=data_sim$X2)
# estimate dynmic logit model
out = cquad_pseudo(id,yv,X, Ttol=10)
summary(out)

## End(Not run)

Simulated dataset

Description

It contains a dataset simulated from the dynamic logit model

Usage

data(data_sim)

Format

The observations are for 1000 sample units at 5 five time occasions:

id

list of the reference unit of each observation

time

number of the time occasion

X1

first covariate

X2

second covariate

y

response

Examples

data(data_sim)
head(data_sim)

Print output for class cquad

Description

Print output for class cquad and output provided by cquad_basic, cquad_equ, cquad_ext, cquad_pseudo

Usage

## S3 method for class 'cquad'
print(x, ...)

Arguments

x

output of class cquad

...

further arguments passed to or from other methods

Author(s)

Francesco Bartolucci (University of Perugia), Claudia Pigini (University of Ancona "Politecnica delle Marche")


Recursive computation of the conditional likelihood for the Quadratic Exponential Model proposed in Bartolucci & Nigro (2010)

Description

Recursively compute the denominator of the individual conditional likelihood function for the Quadratic Exponential Model, adapted from Krailo & Pike (1984).

Usage

quasi_sym(eta,s,dyn=FALSE,y0=NULL)

Arguments

eta

individual vector of products between covariate and parameters

s

total score of the individual

dyn

TRUE if in the dynamic version; FALSE for the static version (by default)

y0

Individual initial observation for dynamic models

Value

f

value of the denominator

d1

first derivative of the recursive function

dl1

a component of the score function

D2

second derivative of the recursive function

Dl2

a component of the Hessian matrix

Author(s)

Francesco Bartolucci (University of Perugia), Claudia Pigini (University of Ancona "Politecnica delle Marche"), Francesco Valentini (University of Ancona "Politecnica delle Marche")

References

Bartolucci, F. and Nigro, V. (2010), A dynamic model for binary panel data with unobserved heterogeneity admitting a root-n consistent conditional estimator, Econometrica, 78, 719-733.

Bartolucci, F., Valentini. F., & Pigini, C. (2021), Recursive Computation of the Conditional Probability Function of the Quadratic Exponential Model for Binary Panel Data, Computational Economics, https://doi.org/10.1007/s10614-021-10218-2.

Krailo, M. D., & Pike, M. C. (1984). Algorithm AS 196: conditional multivariate logistic analysis of stratified case-control studies, Journal of the Royal Statistical Society. Series C (Applied Statistics), 33(1), 95-103.


Recursive computation of the conditional likelihood for the Modified Quadratic Exponential Model proposed in Bartolucci et al. (2018)

Description

Recursively compute the denominator of the individual conditional likelihood function for the Modified Quadratic Exponential Model recursively, adapted from Krailo & Pike (1984).

Usage

quasi_sym_equ(eta,s,y0=NULL)

Arguments

eta

individual vector of products between covariate and parameters

s

total score of the individual

y0

Individual initial observation for dynamic models

Value

f

value of the denominator

d1

first derivative of the recursive function

dl1

a component of the score function

D2

second derivative of the recursive function

Dl2

a component of the Hessian matrix

Author(s)

Francesco Bartolucci (University of Perugia), Claudia Pigini (University of Ancona "Politecnica delle Marche"), Francesco Valentini (University of Ancona "Politecnica delle Marche")

References

Bartolucci, F. and Nigro, V. (2010), A dynamic model for binary panel data with unobserved heterogeneity admitting a root-n consistent conditional estimator, Econometrica, 78, 719-733.

Bartolucci, F., Nigro, V., & Pigini, C. (2018). Testing for state dependence in binary panel data with individual covariates by a modified quadratic exponential model. Econometric Reviews, 37(1), 61-88.

Bartolucci, F., Valentini. F., & Pigini, C. (2021), Recursive Computation of the Conditional Probability Function of the Quadratic Exponential Model for Binary Panel Data, Computational Economics, https://doi.org/10.1007/s10614-021-10218-2.

Krailo, M. D., & Pike, M. C. (1984). Algorithm AS 196: conditional multivariate logistic analysis of stratified case-control studies, Journal of the Royal Statistical Society. Series C (Applied Statistics), 33(1), 95-103.


Recursive computation of pseudo conditional maximum likelihood method proposed by Bartolucci & Nigro (2012).

Description

Recursively compute the denominator of the individual conditional likelihood function for the pseudo conditional maximum likelihood method proposed by Bartolucci & Nigro (2012) recursively, adapted from Krailo & Pike (1984).

Usage

quasi_sym_pseudo(eta,qi,s,y0=NULL)

Arguments

eta

individual vector of products between covariate and parameters

s

total score of the individual

qi

Vector of quantities from first step estimation

y0

Individual initial observation for dynamic models

Value

f

value of the denominator

d1

first derivative of the recursive function

dl1

a component of the score function

D2

second derivative of the recursive function

Dl2

a component for the Hessian matrix

Author(s)

Francesco Bartolucci (University of Perugia), Claudia Pigini (University of Ancona "Politecnica delle Marche"), Francesco Valentini (University of Ancona "Politecnica delle Marche")

References

Bartolucci, F. and Nigro, V. (2010), A dynamic model for binary panel data with unobserved heterogeneity admitting a root-n consistent conditional estimator, Econometrica, 78, 719-733.

Bartolucci, F. and Nigro, V. (2012), Pseudo conditional maximum likelihood estimation of the dynamic logit model for binary panel data, Journal of Econometrics, 170, 102-116.

Bartolucci, F., Valentini. F., & Pigini, C. (2021), Recursive Computation of the Conditional Probability Function of the Quadratic Exponential Model for Binary Panel Data, Computational Economics, https://doi.org/10.1007/s10614-021-10218-2.

Krailo, M. D., & Pike, M. C. (1984). Algorithm AS 196: conditional multivariate logistic analysis of stratified case-control studies, Journal of the Royal Statistical Society. Series C (Applied Statistics), 33(1), 95-103.


Simulate data from the dynamic logit model

Description

Simulate data from the dynamic logit model given a set of covariates and a vector of parameters.

Usage

sim_panel_logit(id, al, X = NULL, eta, dyn = FALSE)

Arguments

id

list of the reference unit of each observation

al

list of individual specific effects

X

corresponding matrix of covariates (optional)

eta

vector of parameters

dyn

TRUE if in the dynamic version; FALSE for the static version (by default)

Value

yv

simulated vector of binary response variables

pv

vector of probabilities of "success"

Author(s)

Francesco Bartolucci (University of Perugia), Claudia Pigini (University of Ancona "Politecnica delle Marche")

Examples

# simulate data from the static logit model
n = 1000; TT = 5                 # sample size, number of time occasions
id = (1:n)%x%rep(1,TT)           # vector of indices
al = rnorm(n)                    # simulate alpha
X = matrix(rnorm(2*n*TT),n*TT,2) # simulate two covariates
eta1 = c(1,-1)                 # vector of parameters
out = sim_panel_logit(id,al,X,eta1)
y1 = out$yv

# simulate data from the dynamic logit model
eta2 = c(1,-1,2)            # vector of parameters including state dependence
out = sim_panel_logit(id,al,X,eta2,dyn=TRUE)
y2 = out$yv

Generate binary sequences

Description

Generate binary sequences of a certain length and with a certain sum.

Usage

sq(J, s = NULL)

Arguments

J

length of the binary sequences

s

sum of the binary sequences (optional)

Value

M

Matrix of binary configurations

Author(s)

Francesco Bartolucci (University of Perugia)

Examples

# generage all sequence of 5 binary variables
sq(5)
# generage all sequence of 5 binary variables, with sum equal 2
sq(5,2)

Summary for class cquad

Description

Summarize the output for class cquad provided by cquad_basic, cquad_equ, cquad_ext, cquad_pseudo

Usage

## S3 method for class 'cquad'
summary(object, ...)

Arguments

object

output of class cquad

...

further arguments passed to or from other methods

Author(s)

Francesco Bartolucci (University of Perugia), Claudia Pigini (University of Ancona "Politecnica delle Marche")