Robust Bayesian small area estimation
Section 4. Final remarks
The
paper considers small area models for handling area level data. The new feature
of this article is modeling both small area means and variances along with the
use of
distribution of random
effects. It is shown via both data analysis and simulation that the proposed
method performs mostly better than the models of You and Chapman (2006) and
Sugasawa et al. (2017) in most situations.
Acknowledgements
Ghosh’s
research was partially supported in part by NSF Grant SES-1327359.
Appendix A
Proof
Theorem 2. Under the model (2.1) with modified Jeffreys’ prior (2.3), the posterior
distribution (2.4) is proper, provided
Proof. Recall the posterior distribution (2.4),
where
First
of all, since
by Stirling’s approximation, we have
and
This leads to
and
Hence this approximation simplifies the last term in (2.4). The
corresponding posterior is
First, integrating out with respect to
By letting
i.e.,
we have
where
Note that
is non-negative definite. Using
as a generic constant which depends only on
the data
we integrate out with respect to
and
respectively in order, we have
and then
Note that
After integrating out with respect to
we have
Finally,
since
where
if
modified Jeffrey’s prior leads to a proper
posterior.
Appendix B
Full conditional distributions
The
full posterior of the parameters given the data is specified in (A.1). For the
MCMC implementation, it is convenient to use the latent parameters
such that
Let
The full conditional distributions are
I.
II.
III.
IV.
V.
and
VI.
All
but (VI) requires the generation of samples from standard distributions. While
we use the Gibbs sampling method for (I)-(V), we use the Metropolis-Hastings
algorithm for generating samples from (VI) as given in Chib and Greenberg
(1995).
How to apply the result of
Chib and Greenberg (1995) to (IV) in (B.1).
If
the target density
can be written as
where
is a density that can be sampled and
is uniformly bounded, then one can set
as a candidate density to draw samples and use
in
which is the probability of move.
Recall
that the full conditional distribution of
is
Since
the second
term above is bounded by
Hence, we can apply third method in the
Section 5 of Chib and Greenberg (1995) with
and
Here
is a candidate-generating density, and
is uniformly bounded.
References
Arora, V., and Lahiri, P.
(1997). On the superiority of the Bayesian method over the BLUP in small area
estimation problems. Stastica Sinica, 7, 1053-1063.
Battese, G.E., Harter,
R.M. and Fuller, W.A. (1988). An error component model for prediction of mean
crop areas using survey and satellite data. Journal of the American
Statistical Association, 95,
28-36.
Bell, W.R. (2008).
Examining sensitivity of small area inferences to uncertainty about sampling
error variances. In Proceedings of
the Survey Research Methods Section, American Statistical Association,
327-333.
Bell, W.R., and Huang,
E.T. (2006). Using the
distribution to
deal with outliers in small area estimation. Proceedings: Symposium 2006, Methodological Issues in Measuring
Population Health, Statistics Canada.
Butar, F., and Lahiri, P.
(2002). On the measures of uncertainty of empirical Bayes small-area
estimators. Journal of Statistical Planning and Inference, 112, 63-76.
Chib, S., and Greenberg,
E. (1995). Understanding the Metropolis-Hastings Algorithm. The American
Statistician, 49, 327-335.
Dass, S.C., Maiti, T.,
Ren, H. and Sinha, S. (2012). Confidence interval estimation of small area
parameters shrinking both means and variances. Survey Methodology, 38, 2, 173-187. Paper available at https://www150.statcan.gc.ca/n1/pub/12-001-x/2012002/article/11756-eng.pdf.
Datta, G.S., and Lahiri,
P. (1995). Robust hierarchical Bayes estimation of small area characteristics
in the presence of outliers. Journal of Multivariate Analysis, 54, 310-328.
Fay, R.E., and Herriot,
R.A. (1979). Estimates of income for small places: An application of
James-Stein procedures to census data. Journal of the American Statistical
Association, 74, 269-277.
Fernandez, C., and Steel,
M.F.J. (1998). On Bayesian modeling of fat tails and skewness. Journal of
the American Statistical Association, 93, 359-371.
Fonseca, T.C.O.,
Ferreira, M.A.R. and Migon, H.S. (2008). Objective Bayesian analysis for the student
regression
model. Biometrika, 95,
325-333.
Jacquier, E., Polson,
N.G. and Rossi, P.E. (2004). Bayesian analysis of stochastic volatility models
with fat-tails and correlated errors. Journal of Econometrics, 122, 185-212.
Jiang, J., Lahiri, P. and
Wan, S. (2002). A unified jackknife theory for empirical best prediction with
M-estimation. Annals of Statistics, 30, 1782-1810.
Lahiri, P., and Rao,
J.N.K. (1995). Robust estimation of mean square error of small area estimators. Journal of the American Statistical Association, 90, 758-766.
Lange, K.L., Little,
R.J.A. and Taylor, J.M.G. (1989). Robust statistical modeling using the
distribution. Journal
of the American Statistical Association, 84, 881-896.
Maiti, T., Ren, H. and
Sinha, A. (2014). Prediction error of small area predictors shrinking both
means and variances. Scandinavian Journal of Statistics, 41, 775-790.
Otto, M.C., and Bell,
W.R. (1995). Sampling error modelling of poverty and income statistics for
states. In Proceedings of the Section
on Government Statistics, American Statistical Association, 160-165.
Rivest, L.-P., and
Vandal, N. (2003). Mean squared error estimation for small areas when the small
area variances are estimated. In Proceedings
of the International Conference on Recent Advances in Survey Sampling.
Slud, E.V., and Maiti, T.
(2006). Mean-squared error estimation in transformed Fay-Herriot models. Journal
of Royal Statistical Society, Series B, 68, 239-257.
Sugasawa, S., Tamae, H.
and Kubokawa, T. (2017). Bayesian estimators for small area models shrinking
both means and variances. Scandinavian Journal of Statistics, 44, 150-167.
Vrontos, I.D.,
Dellaportas, P. and Politis, D.N. (2000). Full Bayesian inference for GARCH and
EGARCH models. Journal of Business and Economic Statistics, 18, 187-198.
Wang, J., and Fuller, W.
(2003). The mean squared error of small area predictors constructed with
estimated error variances. Journal of the American Statistical Association,
98, 716-723.
You, Y., and Chapman, B.
(2006). Small area estimation using area level models and estimated sampling
variances. Survey Methodology, 32,
1, 97-103. Paper available at https://www150.statcan.gc.ca/n1/pub/12-001-x/2006001/article/9263-eng.pdf.