Because Ukraine has more granular flow data, using a simple model that considers the mean flow from the previous

week is reasonable (after the initial hump) for international migration.

When a crisis emerges, public organic data sources are a viable option for modeling the changing dynamics of flow.

For this crisis, Google trends data (generally) is the best organic data signal for retrospective analysis and

nowcasting. All organic sources captured the two phases of the crisis.

For longer term forecasting in countries with more sparse flow data, more variables are needed and models that quantify

uncertainty and allow for more variation in temporal and spatial resolution are important (hierarchical Bayesian).