Migration Trends v4.0 - Permanent vs. Seasonal

What's new in v4.0?

In v4.0, the Migration criterion has been refined to detect panelists who have changed their homes for extended periods. Previously, a 2-month threshold indicated migration, but now, the distinction is made between those who have moved for 2-5 months or those who have moved for 5+ months. This adjustment acknowledges temporary migrations, such as Snowbirds or Students, who often return within 5 months.

The concept of 'Net Migration' now considers only individuals who have moved for 5 or more months. The distinction between 'Permanent Residents' and 'Seasonal Visitors' is introduced. The "fixed population" of an area includes only those who have stayed for at least 5 months, and the term adjusted population is replaced by permanent residents population.

The calculation for Permanent Residents Population takes into consideration the previous month's population, net migration of people moving for over 5 months, natural growth, and international migration.

The count of Seasonal Visitors for each region now includes people who have moved for periods between 2 and 5 months.

There is a change in the schema of the Net files to accommodate the new metric seasonal visitors, and this column is recalculated and refreshed monthly. We still maintain a 2-month latency for the net files (including net migration, permanent residents population, and seasonal visitors), but the latency for the ab files is increased from 2 to 5 months. This affects migration metrics relying on ab files.

v4.0 also introduces a year-by-year adjustment of weights to align annual net migration with Census numbers. Other schema details, file types, naming conventions, metric names, data latencies, and reported granularities remain unchanged from the previous Migration feed (V3.2).


Schema change alert

In order to support the new above described logic, the following changes take place:

net files

  • The column adjustedpopulation is replaces by _permanent_residents
  • A new column seasonal_visitors is added

ab files

  • The column [region_code]_a_adjusted_population is replaced by [region_code]_a_permanent_residents