Can you predict a recession by looking at pregnancy rates? | Hacker News Reader

Can you predict a recession by looking at pregnancy rates?

bbc.com

41 pointsMaysonL28 comments

The graph doesn't look like pregnancy rates precede recessions at all, it looks like they occur at the same time (and thus aren't good for prediction). What's going on is that we have a goofy rule for recessions that require continuous retraction for a recession to be official. In most of these recessions it looks like the economy peaked the same time as pregnancy rates, but a tiny upward blip two quarters later prevented us from being officially in a recession. If you smoothed the idea of a recession into something like "contraction in 3 out of 4 quarters" you wouldn't have tiny blips delaying the official recession, and you wouldn't see pregnancy rates preceding anything, they would just be following the rest of the economy.

You can predict a recession by observing that spending goes down before the recession actually happens. Observe, for instance, that this happens for many things, including stock prices : they drop before the recession. People buying stuff, goes down before recession starts. Etc.

Pregnancies are simply something that get planned out. You make sure you have room, things have to be going well, you only do it if you feel comfortable about your employment. And so on and so forth. They're an indicator, sure, but keep in mind that there's many indicators. From sandwiches eaten to car sales, everything drops before the recession happens (well, except "sin stocks").

People will reply that that's a recession being predicted by a lot of people. That's not really true. It's many actors reacting to each other. In many cases (almost every last example, although there are exceptions), recessions are caused by the government raising interest rates, after having kept them down. This forces companies and consumers alike to accept the truth about decisions they've made in the past few years (since rolling forward debt becomes harder, and thus at the margin impossible).

By observing what's currently happening with sales figures in a lot of sectors I would say we're at the beginning of the transition into the recession, 6-12 months before the actual recession in GDP figures. The stock market top is ~now (as in just passed, or perhaps coming up any second now), and everybody in the financial industry pretty much knows what's coming (but a lot of players cannot currently act upon that for various reasons).

Given just how low interest rates were (ie. < 0), and for how long (~10 years), the next recession ought to be a doozy. Lots of debt needs to be worked out of the system.

The title of the article glosses over one significant fact: You cannot know the pregnancy rate at the precise moment from (1) folks who do not know, (2) folks who will abort or lose the child (worsening economy, loss of job, stress...) (3) folks who do not report. It can be argued that you can abstract those cases out, but the useable data becomes extremely blurry as the early months of a pregnancy are the riskiest ones for the birth.

In hindsight, looking at the recorded birth and subtracting 9 months will give you a clearer picture but by then better indicators of recession in progress might have been more readily observable.

Nevertheless - I find the idea fascinating as the birth of a child is one where individuals have to take into account a lot of things and internalize/assess the situation for the immediate future beyond what folks want to hear or believe.

What I wonder about is the impact of those lost births on future economies (20 years later?) and/or what the impact is on the recovering economy.

From the paper (preprint found here [1]), you are correct in how they reconstruct this information. They use birth data (including estimates of gestation period) to derive the pregnancy rate at a moment in the past. They also attempt to compensate for miscarriages and abortions.

I think your central conclusion is sound, though, namely that this cannot be used to predict the future because there's no reliable data source to give the pregnancy rate in the present.

On the other hand, it might be possible to show that even excluding your (1), (2), and (3), it would still make a reliable predictor. But I'm not sure that there are datasets that would allow any insight even into the number of reported pregnancies. Potentially pharmacies would have access to rudimentary proxies in the form of sales of pregnancy tests, or inverse proxies in the form of sales of contraceptives. Large companies might have information on parental leave, but in the lead-up to a recession, you might have the confounding variable that people are losing their jobs at a higher rate, leading to a direct correlation that might overstate the phenomenon.

[1] https://www3.nd.edu/~kbuckles/BHL_fertility.pdf

Not to mention that if you rely on estimating pregnancy rates by taking birth rates and then shifting backwards nine months, you have lost three quarters of time, and thus there is no way to use this data to predict a recession even if pregnancy rates do precede a recession by three quarters. So it's fun to look at, but ultimately useless for forecasting if you can't get real time pregnancy rates instead of waiting nine months.

If people are choosing to have fewer babies before recessions, their decisions must be made based on some information they have. So looking at pregnancies is interesting, but at best it shows there’s something still missing. And trying to find that might be a little less intrusive then looking into pregnancies.

We could make it a law that if you become pregnant you must report it so that the government can use the data to protect all citizens against recessions. If you don't report it it could be made law that you lose your medical insurance or something.

It could be that people having fewer babies causes recessions. Babies, even before they are born, require a fair amount of economic activity to prepare and later care for them. When that activity slows it may be enough to ripple through the rest of the economy.

But certainly more research is needed.

This article uses the word “conceptions” throughout, but it sounds like the only data is about births. These births would have all occurred after the recessions started.

Did the original paper rule out the hypothesis that the recession actually affected births via an increase in miscarriages and abortions instead? I can’t access it.

Birth - 9 months = conception (on average)

Yeah, that misses out on stillbirths and miscarriages.

Miscarriages maybe but I believe stillbirths are legally required to be recorded. As unpleasant and upsetting as it is, it would be an interesting data point in it's own regard to observe.

Unfortunately, I have lot of personal experience here. The reporting on still births varies greatly. Some states require it past week 16, others stipulate a birth weight, and others set more arbitrary criteria. You would have to account for a lot of external factors.

According to the paper, "The data include the infant’s month of birth, and a clinical estimate of gestation in weeks, which we use to estimate a month of conception."

On miscarriages, "We interpret these data with caution because they come from a subset of one state, and because fetal deaths are under-reported. Nevertheless, the data provide no evidence of an increase in miscarriages leading up to recessions that is anywhere near the magnitude required to explain a significant portion of the observed decrease in births." They similarly argue that abortions aren't significant enough to explain the reduction in births.

“We were surprised when we saw [the correlation] and then we were surprised no one had noticed it before“

Seems like lots of women noticed it. Just sayin’.

Probably not considering the drop on the graph isn't much bigger than some previous drops after which nothing happened...

Recessions are roughly coincident with unemployment claims, so maybe this is signal from water cooler talk... ex. things aren’t looking great at the office, possible layoffs on the horizon, low profits to be announced, or the like, upend future plans for having children?

To add to your grain of salt, I've had quite a number of quotes (I'm a consultant) in the last 3 months that have gone nowhere. These are for firms that I've worked with for years that are all of a sudden very tightfisted about projects that they would have shoveled money at before.

From the chart I just can see that GDP can predict conceptions. GDP falls, conceptions falls, then came the recesion. GDP begins to recover, get out of recession, then conceptions begin.

How does this compare to say... the consumer confidence index? Assuming that everyone is accurately stating their confidence, I don't see why conception data should be ahead of consumer confidence.

>Economists are frequently criticised for failing to accurately predict the direction of economic growth

OT: Do people honestly think that? I thought the academic consensus is that boom/bust cycles are pretty much impossible to predict.

It's possible that there's some autogenic component to pregnancy that is a superior indicator of confidence than self-reporting, though it seems like a farfetched explanation.

The whole premise is nonsensical, imo. It is like saying you can predict stock market crashes based on how many people are long/short VIX.

I thought it was fairly obvious that they can’t be predicted with any reliability, because a reliable prediction will change people’s behavior and break it. Sort of an economic Halting Problem.

Anyone know what kind of data is publicly available on pregnancy rates?

You can probably extrapolate from search data such as Google Trends or the popularity of pregnancy websites through Alexa rankings.

Here's a time series that updates for anyone interested (although clearly has a large lag)

Reply on news.ycombinator.com