The relationship between mobile phone derived movement variables and national census derived migration variables.

The total outgoing and incoming flows from movement between counties were quantified. Movement variables were defined for both various trip durations and the average number of trips over different time frames. All trip duration variables (Len. Week – Len. 4 months) measured the total number of trips that lasted up to the variable name, i.e. Len. Week measures trips lasting up to one week. The average number of trip variables (Avg. Daily – Yearly) measures the trips for various time frames, i.e. Avg. Daily measures the average number of trips each day. For each movement variable, these values were ranked and compared with the ranked values from the total outgoing/incoming movement of individuals from the national census. The census measured responses to the question, ‘where did you live one year ago?’. A linear regression was used to quantify the relationship with adjusted R-squared values presented. Note for all movement variables, p<0.0001.