pln_linear {endogeneity}R Documentation

Recursive PLN-Linear Model

Description

Estimate a Poisson Lognormal model (first-stage) and a linear model (second-stage) with bivariate normally distributed error terms. This command still works if the first-stage dependent variable is not a regressor in the second stage.

Usage

pln_linear(
  form_pln,
  form_linear,
  data = NULL,
  par = NULL,
  method = "BFGS",
  init = c("zero", "unif", "norm", "default")[4],
  H = 20,
  verbose = 0,
  accu = 10000
)

Arguments

form_pln

Formula for the first-stage Poisson lognormal model

form_linear

Formula for the second-stage linear model

data

Input data, a data frame

par

Starting values for estimates

method

Optimization algorithm.

init

Initialization method

H

Number of quadrature points

verbose

Level of output during estimation. Lowest is 0.

accu

1e12 for low accuracy; 1e7 for moderate accuracy; 10.0 for extremely high accuracy. See optim

Value

A list containing the results of the estimated model

References

Peng, Jing. (2022) Identification of Causal Mechanisms from Randomized Experiments: A Framework for Endogenous Mediation Analysis. Information Systems Research (Forthcoming), Available at SSRN: https://ssrn.com/abstract=3494856

See Also

Other endogeneity: bilinear(), biprobit_latent(), biprobit_partial(), biprobit(), pln_probit(), probit_linear_latent(), probit_linear_partial(), probit_linear()

Examples

library(MASS)
N = 1000
rho = -0.5
set.seed(1)

x = rbinom(N, 1, 0.5)
z = rnorm(N)

e = mvrnorm(N, mu=c(0,0), Sigma=matrix(c(1,rho,rho,1), nrow=2))
e1 = e[,1]
e2 = e[,2]

y1 = rpois(N, exp(1 + x + z + e1))
y2 = 1 + x + y1 + e2

est = pln_linear(y1~x+z, y2~x+y1)
est$estimates

[Package endogeneity version 2.0.1 Index]