Estimating The Probability That A Simulated System Will Be The Best
Multinomial; Ranking and selection; Simulation
Consider a stochastic simulation experiment consisting of v independent vector replications consisting of an observation from each of k independent systems. Typical system comparisons are based on mean (long-run) performance. However, the probability that a system will actually be the best is sometimes more relevant, and can provide a very different perspective than the systems' means. Empirically, we select one system as the best performer (i.e., it wins) on each replication. Each system has an unknown constant probability of winning on any replication and the numbers of wins for the individual systems follow a multinomial distribution. Procedures exist for selecting the system with the largest probability of being the best. This paper addresses the companion problem of estimating the probability that each system will be the best. The maximum likelihood estimators (MLEs) of the multinomial cell probabilities for a set of v vector replications across k systems are well known. We use these same v vector replications to form vk unique vectors (termed pseudo-replications) that contain one observation from each system and develop estimators based on Ave (All Vector Comparisons). In other words, we compare every observation from each system with every combination of observations from the remaining systems and note the best performer in each pseudo-replication. Ave provides lower variance estimators of the probability that each system will be the best than the MLEs. We also derive confidence intervals for the Ave point estimators, present a portion of an extensive empirical evaluation and provide a realistic example. © 2002 Wiley Periodicals, Inc. Naval Research Logistics.
Naval Research Logistics
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Miller, J. O.; Nelson, Barry L.; and Reilly, Charles H., "Estimating The Probability That A Simulated System Will Be The Best" (2002). Scopus Export 2000s. 2550.