Assessing the Cost of Population Dynamics Design Options in a Microsimulation

Abstract

We explore microsimulation design options as a source of divergence in total population when using demographic statistics from the United Nations to model population dynamics in three countries between 1950 and 2100. We compare 176 unique model designs, which toggle options such as the time step, the initial sample size of agents, variance reduction, ordering of demographic events, and adjustments to risk assignment as appropriate to each statistic. Results indicate that small population samples and 1-year time steps can produce particularly high divergence from UN targets, even when other options known to reduce divergence are implemented. Small sample 1-year models with low divergence are possible, but the specific combinations of options interact with a country’s population dynamics in unpredictable ways, which prevents the design from being used in other country contexts. These findings are important for balancing efficiency, accuracy, realism, and generalizability in demographic microsimulation design.