mspeNERsumcaR Documentation

Compute MSPE through Sumca method for Nested error regression model

Description

This function returns MSPE estimator with the combination of linearization and resampling appoximation method for Nested error regression model.

Usage

mspeNERsumca(ni, X, Y, Xmean, K = 50, method = 2)

Arguments

ni

(vector). It represents the sample number for every small area.

X

(matrix). Stands for the available auxiliary values.

Y

(vector). It represents the response value for Nested error regression model.

Xmean

(matrix). Stands for the population mean of auxiliary values.

K

(integer). It represents the Monte-Carlo sample size for "Sumca". Default value is 50.

method

The MSPE estimation method to be used. See "Details".

Details

This method was proposed by J. Jiang, P. Lahiri, and T. Nguyen, sumca method combines the advantages of linearization and resampling methods and obtains unified, positive, low-computation burden and second-order unbiased MSPE estimators.

Default value for method is 1, method = 1 represents the MOM method , method = 2 and method = 3 represents ML and REML method, respectively.

Value

This function returns a list with components:

MSPE

(vector) MSPE estimates for NER model.

bhat

(vector) Estimates of the unknown regression coefficients.

sigvhat2

(numeric) Estimates of the area-specific variance component.

sigehat2

(numeric) Estimates of the random error variance component.

Author(s)

Peiwen Xiao, Xiaohui Liu, Yuzi Liu, Jiming Jiang, and Shaochu Liu

References

J. Jiang and M. Torabi. Sumca: simple; unified; monte carlo assisted approach to second order unbiased mean squared prediction error estimation. Journal of the Royal Statistical Society: Series B (Statistical Methodology), 82(2):467-485, 2020.

Examples

### parameter setting 
Ni = 1000; sigmaX = 1.5; m = 10
beta = c(0.5, 1)
sigma_v2 = 0.8; sigma_e2 = 1
ni = sample(seq(1,10), m,replace = TRUE); n = sum(ni)
p = length(beta)
### population function
pop.model = function(Ni, sigmaX, beta, sigma_v2, sigma_e2, m){
  x = rnorm(m * Ni, 1, sqrt(sigmaX)); v = rnorm(m, 0, sqrt(sigma_v2)); y = numeric(m * Ni)
  theta = numeric(m); kk = 1
  for(i in 1 : m){
    sumx = 0
    for(j in 1:Ni){
      sumx = sumx + x[kk]
      y[kk] = beta[1] + beta[2] * x[kk] + v[i] + rnorm(1, 0, sqrt(sigma_e2))
      kk = kk + 1
    }
    meanx = sumx/Ni
    theta[i] = beta[1] + beta[2] * meanx + v[i]
  }
  group = rep(seq(m), each = Ni)
  x = cbind(rep(1, m*Ni), x)
  data = cbind(x, y, group)
  return(list(data = data, theta = theta))
} 
### sample function
sampleXY = function(Ni, ni, m, Population){
  Indx = c()
  for(i in 1:m){
    Indx = c(Indx, sample(c(((i - 1) * Ni + 1) : (i * Ni)), ni[i]))
  }
  Sample = Population[Indx, ]; Nonsample = Population[-Indx, ]
  return(list(Sample, Nonsample))
} 
### data generation process
Population = pop.model(Ni, sigmaX, beta, sigma_v2, sigma_e2, m)$data
XY = sampleXY(Ni, ni, m, Population)[[1]]
X = XY[, 1:p]
Y = XY[, p+1]
Xmean = matrix(NA, m, p)
for(tt in 1: m){
  Xmean[tt, ] = colMeans(Population[which(Population[,p+2] == tt), 1:p])
}
### mspe result
mspeNERsumca(ni, X, Y, Xmean, 50, method = 1)