Title
On Analysis of Incomplete Field Failure Data
Speaker
H. K. Tony Ng, Southern Methodist University
Abstract
Most commercial products in the market place are sold with warranties and they are sold indirectly through dealers. This results in serious missing data problems in the analysis of field return data because of the unobserved sales date for the unreturned units. Our purpose here is to systematically investigate the parametric inference for such data. This study considers a general setting for field failure data with unknown sales dates and a warranty limit. A stochastic expectation-maximization (SEM) algorithm is developed to estimate the distributions of the sales lag (time between shipment to a retailer and sale to a customer) and the lifetime of the product under study. Extensive simulations are used to evaluate the performance of the SEM algorithm and to compare with an imputation-based approach. Real examples are used to illustrate the proposed methodology.
