(Yet More) Changing Migration Profiles

By popular request, I’m posting a snapshot of net migration profiles by age across four time periods for both Metro Vancouver and the Vancouver School District (encompassing both the City of Vancouver and the University Endowment Lands of UBC to its immediate west).  The comparison allows us to see how Vancouver, as a central city, relates to the wider metropolitan area in terms of net migration.  But I’ll also walk more carefully through the steps I’m taking to come up with the figures.  Let’s start with the big picture (click here to make it bigger!).

VanCityMetroNetMig1986-2015

Here I’m comparing net migration figures by age groups (aggregated for simpler presentation) across four time periods for both the Vancouver School District and the metro area.  I toyed around with how to present the data, and went with the Vancouver School District net migration figures in color, and the corresponding metro figures in white.  Of note, and as previously demonstrated, the metro area is growing across nearly all age groups in all time periods.  Only amongst older residents, in their fifties and above, do we see evidence of possible out-migration (and I’d be careful about interpreting this).

For the Vancouver School District (VSD), contained within the metro area, it’s a different story.  Young people, especially of university age, FLOOD into the VSD.  They keep flooding through their twenties, but as they move into their thirties, the flood starts to recede.  As people proceed through their mid-thirties (in red), more of them leave the VSD than enter.  This is a relatively common pattern for central cities, as many thirty-somethings decamp to cheaper and more spacious suburbs nearby.  As visible from the metro stats, more thirty-somethings continue to enter the Metro Area than leave it, even though that’s no longer true for the VSD.

All that said, the historical comparison is interesting!  In relative terms, it looks like Vancouver saw a ramping up of the usual exodus of thirty-somethings between 1986 and 2011.  But in the most recent five-year period, the exodus has slowed again.  Relatively fewer thirty-somethings are fleeing the VSD now than was the case in the previous five-year period.  I’m not sure how much to make of this pattern, but it’s intriguing.

As for the flight of the Millennials, I’m still not seeing it.  Not for Metro, and not for the VSD.  But maybe that’s just because I think of Millennials as the fresh-faced twenty-somethings in my classes now, rather than the dour thirty-somethings of my classes from ten years ago.

How to do it yourself

As with the net migration profiles I ran yesterday, I’m using  BC Stats data from their population estimates.  For Metro data, I’m selecting “Greater Vancouver” from Regional Districts available.  For the City, I’m selecting “Vancouver” from School Districts.  In each case, I use the five year age categories, totaling across both sexes, and I select all years available.

The five year age categories match nicely with five year time comparisons.  Setting aside death and migration, if I knew how many people were ages 5-9 in 1986, then I’d also know exactly how many people would be ages 10-14 in 1991.  But people die and people move around.  To take the former into account, I age everybody five years.  I do this by finding reasonable age-specific mortality rates to apply. This time I chose 2008 mortality rates for all of Canada.  But these rates are worth playing around with; choose your own games to play with death!   Different rates can have sizable effects for older populations, though they won’t matter much for the young.  For good measure,  I killed people off for three years using rates from their starting age bracket, and two from their receiving age bracket.  Then I subtracted how many I had left from my 1986 population from how many people actually showed up to be counted in 1991.  Voila!  The remainder is my estimate of net migration.  Given that most of that migration presumably takes place during the intervening years, I’ve labeled my estimates by mid-ranges, like ages 7-12, centered between 5-9 and 10-14.  There are ways to tinker with this to try and be even more precise, but this exercise should provide a decent estimate of net migration (especially given remaining uncertainties I have about data quality).  If you’ve read this far, you should download the data into a spreadsheet and try it out!

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