Table 2.

Description of simulation model characteristics.^*

	Discrete event simulation (DES)	Agent-based modeling (ABM)
Type of problem	Operational, tactical	Strategic at the policy level (eg, to inform program implementation) Operational at the management level (eg, tactical at the level of logistics, such as scheduling)
Perspective	Process oriented, emphasis on detail complexity (top down)	Individual oriented, dynamic and detail complexity (bottom up)
Handling of time	Discrete	Discrete
Approach	Explanatory	Exploratory and explanatory
Basic building blocks	Entities, events, queues	Autonomous agents, decision rules
Data sources	Numerical with some judgmental elements	Broadly drawn: qualitative and quantitative
Unit of analysis	Queues, events	Decision rules, emergent behavior
Mathematical formulation	Mathematically described with logic operators	Mathematically described with logic operators and decision rules
Outputs	Point predictions, performance measures	Detailed and aggregate key indicators, understanding of emergence due to individual behavior, point predictions
Advantages	Flexible, which facilitates updating Useful for problems for which it is particularly relevant to be able to capture the changing attributes of entities (eg, patients) and for which the processes to be characterized can be described by events	Unique feature of ABM is the ability to capture relationship networks among individuals Well suited to addressing public health planning and policy needs, as well as healthcare infrastructure investment decisions Can help address problems that involve both deterministic and stochastic processes ABM allows testing assumptions about human behavior in response to new information, incentives, or penalties
Disadvantages	Compared with traditional health economic models, DES models are data intensive and require more time to obtain data and data analysis to prepare model inputs compared with traditional health economic models; programming and calibration are usually time-consuming	Compared with traditional health economic models, ABM models are data intensive and require more time to obtain data and data analysis to prepare model inputs; programming and calibration are usually time-consuming

^*Adapted from Marshall et al²² and Caro and Moler.²⁴