Likelihood functions based on parameter-dependent functions

Thomas A. Severini*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Consider likelihood inference about a scalar function ψ of a parameter θ. Two methods of constructing a likelihood function for ψ are conditioning and marginalizing. If, in the model with ψ held fixed, T is ancillary, then a marginal likelihood may be based on the distribution of T, which depends only on ψ; alternatively, if a statistic S is sufficient when ψ is fixed, then a conditional likelihood function may be based on the conditional distribution of the data given S. The statistics T and S are generally required to be the same for each value of ψ. In this paper, we consider the case in which either T or S is allowed to depend on ψ. Hence, we might consider the marginal likelihood function based on a function T ψ or the conditional likelihood given a function S ψ. The properties and construction of marginal and conditional likelihood functions based on parameter-dependent functions are studied. In particular, the case in which Tψ and Sψ may be taken to be functions of the maximum likelihood estimators is considered and approximations to the resulting likelihood functions are presented. The results are illustrated on several examples.

Original languageEnglish (US)
Pages (from-to)421-446
Number of pages26
Issue number3
StatePublished - Jun 2004


  • Ancillary statistics
  • Conditional likelihood
  • Likelihood inference
  • Marginal likelihood
  • Maximum likelihood estimators
  • Modified profile likelihood
  • Nuisance parameters

ASJC Scopus subject areas

  • Statistics and Probability


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