Two important issues in a simulation study are related to how accurate model results are. The first issue is model verification. According to Law and Kelton (2000), verification is concerned with determining whether the conceptual simulation model has been correctly translated into a computer program. Besides model verification for a typical manually created simulation model, data-driven simulation model verification should also be concerned with checking and verification of the programming code (Visual Basic) used to generate the simulation (Arena) model. In the VIVACE WP2.5 work, various techniques have been used to achieve this correct translation from program design stage through programming until after programming testing. These techniques include

• modular program design
• detailed regular code checking and testing
• code and model tracing in debugging mode
• running model under specific conditions where model output can be predicted and
• finally by observing model output animations.

An example of model tracing in debug model is given in the following diagram and that for model output animations in the next.