Proceedings of the 2015 Winter Simulation Conference L. Yilmaz, W. K. V. Chan, I. Moon, T. M. K. Roeder, C. Macal, and M. D. Rossetti, eds. TUTORIAL: SIMULATION METAMODELING Russell R. Barton The Pennsylvania State University Smeal College of Business 210 Business Building University Park, PA 16802 USA ABSTRACT The concept of a metamodel has been an important tool for simulation analysis for forty years. These models of simulation models have the advantage of faster execution, and they can (sometimes) provide insight on the nature of the simulation response as a function of design and input distribution parameters. This introductory tutorial will describe metamodeling uses and associated processes, survey commonly used metamodel types and associated experiment designs, and give a brief description of some recent developments and how they may affect future “mainstream” simulation metamodeling. 1 INTRODUCTION Discrete-event simulation models allow users to examine in relatively high fidelity the expected behavior of manufacturing, transportation, health care or other systems. The simulation model can be exercised at lower cost and with less risk than the real system. Further, the real system may not yet exist, so simulation provides performance prediction for the as-yet-to-be-constructed real system. Exercising such a model in an ad hoc way may not lead to general insights on the behavior of the real (either extant or imagined) system being modeled, however. Further, when the simulation model fidelity is high and the system is complex, the computational effort to simulate can be substantial. Simulationists then often fit a computationally efficient approximation to the simulation model: a metamodel. In this introductory tutorial we examine the role of metamodels and the metamodeling activity in simulation studies. Metamodeling permits special insights into system performance, and enables extensive exercise of the system under different design conditions at relatively modest computational cost. This is the first WSC introductory tutorial focused on metamodeling in at least seventeen years (Barton 1998). Closely related tutorials on the design of simulation experiments appear regularly, however. See for example the tutorials by Law (2014), Sanchez and Wan (2012), Barton (2010), and Kleijnen (2008). This is not to say that the field is not active: there have been many papers on new metamodeling methods and on new uses for simulation metamodels. At WSC‘14 alone there were two sessions dedicated to metamodeling, and a total of ten papers across all sessions. And see the very good advanced tutorial by Staum (2009). This tutorial will provide an accessible view to metamodeling for the beginner. For that reason, open access materials receive preference: a reference to a Management Science paper may be omitted in favor of an earlier WSC publication - these can be freely accessed under the Archive link at the WSC home page (www.wintersim.org). Advanced methods will not be the focus. While this tutorial will discuss the design of simulation experiments, the emphasis will be on the historical context of metamodeling, metamodel types, and the ultimate uses of metamodels, with guidance on the overall metamodeling process. 1765 978-1-4673-9743-8/15/$31.00 ©2015 IEEE