TY - JOUR TI - Sima – an Open-source Simulation Framework for Realistic Large-scale Individual-level Data Generation AU - Tikka, Santtu AU - Hakanen, Jussi AU - Saarela, Mirka AU - Karvanen, Juha VL - 14 IS - 3 PY - 2021 DA - 2021/12/31 SP - 27-53 C1 - IJM 2021;14(3):27-53 DO - 10.34196/ijm.00240 UR - https://doi.org/10.34196/ijm.00240 AB - We propose a framework for realistic data generation and the simulation of complex systems and demonstrate its capabilities in a health domain example. The main use cases of the framework are predicting the development of variables of interest, evaluating the impact of interventions and policy decisions, and supporting statistical method development. We present the fundamentals of the framework by using rigorous mathematical definitions. The framework supports calibration to a real population as well as various manipulations and data collection processes. The freely available open-source implementation in R embraces efficient data structures, parallel computing, and fast random number generation, hence ensuring reproducibility and scalability. With the framework, it is possible to run daily-level simulations for populations of millions of individuals for decades of simulated time. An example using the occurrence of stroke, type 2 diabetes, and mortality illustrates the usage of the framework in the Finnish context. In the example, we demonstrate the data collection functionality by studying the impact of nonparticipation on the estimated risk models and interventions related to controlling excessive salt consumption. KW - calibration KW - data collection KW - discrete event simulation KW - interventions KW - missing data KW - synthetic data JF - IJM SN - 1747-5864 PB - International Journal of Microsimulation ER -