So the population projection is going and as we work along with it you get to look at some data you did not look at in a while. Lots of recent discussion for us focuses on fertility and fertility modeling. Specifically we are trying to determine various determining factors related to births for North Dakota. This is important given the recent booms in certain sectors and in certain regions of the state.
So looking at the data there was one map I decided to generate to see what it looked like.
So you can see the map displays county level birth ratio, specifically of births to unmarried women to births for married women. A little side note the ratio needs to be in this fashion as there are some counties with zero births to unmarried women. Those obviously cannot be in the denominator. So the range does go from zero to a high of 9.7 based on this census data.
So the high points are interesting, but so is the consistency across the state. The mean for the ratio is .6765 and the median is .3448 with a standard deviation of 1.5367. The 75th percentile is at 0.5000 actually. The lower ratio means many, if not most, of the births in North Dakota are to married women.
Even in a place like Williams County where there are significant changes in economic structure due to the oil industry the ratio is less than 0.20. As I said, a piece of data I had not seen in a time and we came across it in our discussions of fertility as part of our projection for the North Dakota population.