Understanding sub-national patterns

• But what is happening sub-nationally?

• Within a system of 408x408 zones, the total number of possible flows to analyse = 166,464

• A system for aggregating these spatial units into fewer groups is required, but which system is appropriate/most useful?

• Larger administrative units – e.g. Regions?
• Classification based on area characteristics?

• General purpose classifications used successfully in internal migration analysis before (Raymer and Giulietti, 2009, Dennett and Stillwell, 2010)