Replacement was another idea we talked about in the population analysis class this week. Essentially it is an estimate of the deaths and migratory outflows from the area over a specified period of time and is called replacement because it is what you would need to replace in order for population to remain the same. Not really terribly complicated, but it is a nice complement to the idea of turnover and I generated both the level and the rate for counties in North Dakota.
I am teaching population analysis to the undergraduates this year which is a first for me and them. We talked about the simple calculation of growth rates and how population change is actually more complicated and subtle than an overall population growth rate. This got us to the idea of turnover, that is just measuring the births, deaths, inflows, and outflows that go into the changing population. Basically just seeing how much is changing compared to the overall population level. So I thought I would have some fun and apply this to North Dakota. This could be especially important given that some North Dakota counties experienced high degrees of population change due to economic circumstances.