My current research focuses on fertility behavior in response to a variety of economic conditions. This includes partner and own employment type as well as in response to the changes in economic cycle. One of the latter pieces is an examination of the response to the oil boom and then bust in North Dakota. The graph below shows the last ten years or so of fertility rates by age category. It is a fertility rate because it is births divided by women in the specific child-bearing age category as opposed to a crude birth rate.
Clearly these are not completely identical but the consistency is pretty remarkable given the dramatic change in economic circumstances given the nature of the oil boom. This is at the state level so there are a few things that may need to be considered.
State level is too aggregated? Perhaps the state level is too large an area to look for the change, especially since the oil boom was very geographically specific. True there were broad economic gains across the state, but perhaps the indirect effects would not induce a change in fertility behavior.
Movement within the state? Perhaps people moved within the state and the county level will bear out some changes in the fertility behavior. I see changes in the county level birth data but it still needs to be controlled for a variety of different economic and other circumstances.
How did people interpret the boom? Did people interpret the oil boom as a temporary event? If they did then it could be a tempo change, not a quantum difference. It is entirely possible this is the case but the cohort change is not fully realized yet so it is certainly incomplete.
So much research and so little time.