U.S. marriage rates are falling generally, so that’s the real news. And it’s important. In fact, one classic projection has the rate hitting zero at 2042. But the news shenanigans are in the prediction business.
I first wrote here about Demographic Intelligence, a profit-making venture founded by Brad Wilcox (full file). They prey on companies’ ignorance about demography and the news media’s desire to stay ahead of the story, making ridiculous claims like “99% accuracy” in their forecasts. Here’s an update.
In a Washington Post Wonkblog entry meaninglessly titled, “Why parents should stop hoping their kids will get married,” we read:
“Millennials are such a big generation, we’re going to have more people of prime marriage age in the next five years than we’ve had at any time in U.S. history. For that alone, we’d expect an uptick in marriage rates,” said Sam Sturgeon, president of Demographic Intelligence.
Setting aside the knowledge-sucking obsession with generational marketing terms, let’s just hold the president of a company with “demographic” in the title to a slightly-higher-than-complete-nonsense standard of demographic intelligence. The median age at marriage is now 28 (combining men and women). At that age there were 4.3 million people in 2013. That is actually the highest number of people ever at the median age at marriage. For example, in 1900, when the median age at marriage was 24, there were only 1.5 million people that age. Wow!
However, intelligent demographer Sturgeon said “for that alone, we’d expect an uptick in marriage rates.” And marriage rates are based on population size. that 4.3 million people at age 28 in 2013 was only 1.35% of the population, while the 1.5 million people at age 24 in 1900 was 1.96% of the population. In fact, the pattern is the opposite of what Sturgeon said: we have never had fewer people — proportionately — in the prime marrying age. Double wow!
Here is the population distribution by age from 1900 to 2013, from the IPUMS.org online table maker (try it, it’s easy!). The color coding helpfully shows where the number is above average (red) versus below average (blue). I’ve highlighted the five-year age interval that contains the median marriage age for each decade:
That the marriage rate is falling — Sturgeon’s expert prediction (see below) is that it will reach an all-time low in 2016 (as it has in 16 of the last 33 years) — is in large part driven by this age composition trend.
How accurate is that forecast?
Demographic Intelligence boasts “99% accuracy” in its wedding forecasts. And these forecasts, they say, are very useful:
This unique forecast is especially valuable as the federal marriage statistics are usually released 12 to 24 months after the date to which they apply, making official data of limited usefulness to the wedding industry. Our forecast is available 24 months before weddings happen, thereby offering a tremendous value to companies that focus on weddings and ancillary businesses.
Now, I’m all in favor of wasting the wedding industry’s money, but I don’t like deceiving the public. So I have to tell you: for every year from 2001 to 2012, if you had simply used last year’s marriage rate to predict this year’s, you would have averaged 98.3% accuracy. That is the deer-in-headlights method of forecasting. In fact, the deer-in-the-headlights forecast for 2012 — that is, assuming no change from 2011 — yields an astonishing accuracy of 99.87% (see below). Not bad! I’ll sell that to you for just 98% of what Demographic Intelligence is charging (except you’re already paying for my services, so you’re welcome).
Of course, demographers like projections, and I’m no exception. It is frustrating that official marriage statistics lag “real time” so much more than other important statistics, such as the unemployment rate or the number of named storms per season. That’s why in 2013 I announced a marriage forecast contest to predict the 2012 marriage rate, and provided some trends in key variables for you to experiment with (in a spreadsheet here): Google searches for wedding invitations, bridal showers, and wedding gifts; the unemployment rate, the Index of Consumer Sentiment, and the number of women ages 20-39:
There was so little interest in my contest (go figure), that I never got around to updating the results. So here goes. We now know from official statistics that there were 2,131,000 marriages in 2012, which, for a population of 313,914,040, yields a marriage-per-1000 rate of 6.788, down from 6.797 in 2011. Using different combinations of these variables, I generated projections using linear regressions. As I noted, the no-change performed very well, at 99.87% accuracy. But the winning model was actually the one that used the Google search trends only, which predicted 2,133,647 weddings, an astonishing 99.88% accurate. If Google is not using their data to get filthy rich — oh wait.
Anyway, in this exercise I’m just predicting the next year in the series — it gets a little trickier if you want to go four years out. And demographic projections are a serious science. But this prediction business is just wasting money and confusing people.