Estimating functions in indirect inference

• 成果类型: Article
• 署名作者: Heggland, K; Frigessi, A
• 署名单位: University of Oslo
• 刊物名称: JOURNAL OF THE ROYAL STATISTICAL SOCIETY SERIES B-STATISTICAL METHODOLOGY
• ISSN/ISSBN: 1369-7412
• DOI: 10.1111/j.1369-7412.2003.05341.x
• 发表日期: 2004
• 页码: 447-462
• 关键词: simulated moments; models

摘要

There are models for which the evaluation of the likelihood is infeasible in practice. For these models the Metropolis-Hastings acceptance probability cannot be easily computed. This is the case, for instance, when only departure times from a G/G/1 queue are observed and inference on the arrival and service distributions are required. Indirect inference is a method to estimate a parameter theta in models whose likelihood function does not have an analytical closed form, but from which random samples can be drawn for fixed values of theta. First an auxiliary model is chosen whose parameter theta can be directly estimated. Next, the parameters in the auxiliary model are estimated for the original data, leading to an estimate (beta) over cap. The parameter beta is also estimated by using several sampled data sets, simulated from the original model for different values of the original parameter beta. Finally, the parameter beta which leads to the best match to is chosen as the indirect inference estimate. We analyse which properties an auxiliary model should have to give satisfactory indirect inference. We look at the situation where the data are summarized in a vector statistic T, and the auxiliary model is chosen so that inference on beta is drawn from T only. Under appropriate assumptions the asymptotic covariance matrix of the indirect estimators is proportional to the asymptotic covariance matrix of T and componentwise inversely proportional to the square of the derivative, with respect to theta, of the expected value of T. We discuss how these results can be used in selecting good estimating functions. We apply our findings to the queuing problem.