Kalbfleisch, J.D.; Lawless, J.F. (1988, ASQC and the American Statistical Association) University of Waterloo, Canada
Editor's Note: This article and the accompanying discussions were presented at the Technometrics session of the 32nd Annual Fall Technical Conference, cosponsored by the Chemical and Process Industries and the Statistics Divisions of the American Society for Quality Control and the Section on Physical and Engineering Sciences of the American Statistical Association. The conference was held in East Rutherford, New Jersey, October 20-21, 1988.Likelihood-based methods are developed for the analysis of field-performance studies with particular attention centered on the estimation of regression coefficients in parametric models. Failure-record data are those in which the time to failure and the regressor variables are observed only for those items that fail in some prespecified follow-up or warranty period. It is noted that for satisfactory inference about baseline failure rates or regression effects it is usually necessary to supplement the failure-record data either by incorporating specific prior information about x or by taking a supplementary sample of items that survive To. General methods are outlined and specific formulas for various likelihood-based methods are obtained when the failure-time model is exponential or Weibull. In these models the methods are compared with respect to asymptotic efficiency of estimation. Several extensions to more complicated sampling plans are considered.
Data collection,Likelihood methods,Regression analysis,Reliability,Warranties,Weibull analysis