Search Results | Publications

You searched for:

Author: N.G. Shephard

4 results found.

Econometrics Paper

Estimation and Testing of Stochastic Variance Models

Andrew C Harvey and N.G. Shephard

A stochastic variance model may be estimated by quasi-maximum likelihood procedure by transforming to a linear state space form. The properties of observations corrected for heteroscedasticity can be derived. A model wit...Read more...

1993

Econometrics Paper

Exact Score for Time Series Models in State Space Form (Now published in Biometrika (1992), 79, 4, pp.283-6.)

Siem Jan Koopman and N.G. Shephard

The score vector for a time series model which fits into the Gaussian state space form can be approximated by numerically differentiating the log-likelihood. If the parameter vector is of length p, this involves the runn...Read more...

1992

Econometrics Paper

Deletion Diagnostics and Transformations for Time Series

A.C. Atkinson and N.G. Shephard

Deletion diagnostics are developed for structural time series models. These show the effect of the deletion of individual observations on residuals and on the estimates of regression parameters. The methods are extended ...Read more...

1992

Econometrics Paper

A Local Scale Model: An Unobserved Component Alternative to Integrated GARCH Processes (Now published in Journal of Econometrics, vol.60, (1994), pp.181-202.)

N.G. Shephard