Economist Writing Every Day

On X.com Matt Yglesias posted a chart that sparked some conversation about child safety:

One thing about the much-lamented rise of more intensively supervised childhood activities is that kids have in fact become a lot less likely to die. pic.twitter.com/MTjR7spLM8

— Matthew Yglesias (@mattyglesias) October 16, 2023

Of course, it was probably more his comment about the “rise of more intensively supervised childhood activities” that generated the feedback and pushback. And I assume his comment was partially tongue-in-cheek, as often happens on Twitter, and designed to generate that very discussion. Still, it is worth thinking about. Exactly why did that decline happen?

I’ve posted on this topic before. In my March 2023 post, I looked at very broad categories of child death. While all death categories have declined, about half of the decrease (depending on the age group, but half is about right) is from a decline in deaths from diseases, as opposed to external causes. And fewer disease death can largely be attributed to improvements in healthcare, broadly defined. Good news!

Of course, that means that about half of the decline is from things other than diseases. What caused those declines? Let’s look into the data. Specifically, let’s look into the data on deaths from car accidents.

For children ages 5-14, motor vehicle accidents were the largest category of death in 2022 (and this is also true if you look at the cumulative total from 1999-2020 — 2022 was not an outlier). There were about 900 deaths in 2022 from motor vehicle accidents in that age group, which is slightly more than cancer deaths, and quite a bit more than homicide or suicide (just over 1,000 deaths for these two categories combined).

But what was the nature of those deaths? The main categories for victims of motor vehicle accidents are passengers, pedestrians, and bicyclists (or “pedal cyclists” in the CDC data). Here’s the chart for those three categories of victims, summed over an 11-year period, for both a time period when many Baby Boomers were 5-14, as well as recent years (EDIT: I originally was undercounting some of these deaths in both time periods, especially passenger deaths. Sorry!).

When I first created this chart, it was both shocking and I thought it must be wrong (EDIT: and the data was wrong in a few ways!). But I went through the data several times, in several different approaches, and it holds up. There has been a huge decrease in the number of children ages 5-14 killed by motor vehicles (primarily cars, but also including motorcycles, trucks, etc., but not trains or boats). And it’s not because there are fewer kids today: there are actually about 5 percent more than 1968-1978. Overall, the death rate from motor vehicle accidents is about 1/5 of what it was three generations ago (EDIT: originally I had said 1/6).

One astonishing thing about the chart (and again, I had to triple check this [EDIT: should have quadruple checked]) is that most of the car accident deaths in 1968-1978 were pedestrians rather than passengers. And about half as many kids riding bikes as were killed as passengers of cars. For passengers of cars, the death rate fell by about 50 percent (that’s pretty good!), but the drop in child pedestrian deaths and child cyclist deaths in massive. The decline in the death rate for kids ages 5-14 for both pedestrians and bicyclists was about 90 percent (EDIT: originally I said 95 percent). That’s huge. As a comparison, the pedestrian death rate for adults aged 25-54 also fell over this time period, but by a smaller (though still significant) 70 percent. The pedal cyclist death rate for adults aged 25-54 actually rose 50 percent (perhaps due to more adults cycling to work).

Added detail (after the original post): there were another 6,000 motor vehicle deaths in 1968-1978 in this age group that don’t specify whether they were passengers, pedestrians, or something else. There were also over 1,300 deaths for drivers of motor vehicles in the 5-14 age group, about 60% of which were on motorcycles. Once again, my undercounting is bad (sorry!), but since I’m mostly undercounting 1968-1978, these same (welcome) trends have continued.

So why did this happen? The data doesn’t tell us. One possibility, suggested by many, is that kids aren’t out walking around or biking as much as the past. And while I can’t find any good data to confirm or reject this, I suspect that it is true to a large extent. Also, for many that ride bikes today, they are on bike paths or at in least bike lanes.

But many other things could be contributing to this. A few things pushing in the opposite direction are that cars and generally bigger and driving faster today. Given that, the decline is even more notable. But these facts about size and speed could also be a reason that fewer kids are out an about.

We could go further. Safety might be a reason. A lot more kids wear helmets today (though not while walking!). We are also probably better at treating kids that do get hit by cars and aren’t immediately killed. So we’d want even more data! Cars are also safer, but this could go in two ways. For safety improvements that protect the driver, this could mean that they adjust their behavior and drive in a more risky manner. But some safety improvements can help pedestrians/bike riders, such as back-up or other cameras that either alert the driver or force the vehicle to stop.

In the end a lot of these explanations hard to test or quantify, even one-by-one, and to do a general analysis of all the factors is almost impossible. That makes this data very hard to be useful for a parent or child trying to think about risk. And from a social perspective, it makes thinking about tradeoffs hard. Economists love to say things like “the optimal number of kids killed by cars isn’t zero.” Sure enough. By that we mean, in short, that there are costs to not having kids play outside (conversely: there are benefits to having them play outside). But what is the optimal number of deaths? This is hard and perhaps impossible to say from a social perspective. Still me must make decisions.

Take Halloween as an example. Should you let your kids walk around, on the streets, after dark, wearing masks that obstruct their view? Unsupervised or with the parents? Millions of parents face this dilemma every year, and millions of parents… generally let their kids go out candy collecting (often with parental supervision). They do so even knowing (or maybe not?) that Halloween is a deadly night for cars hitting kids. It’s at least twice as deadly as any other night, but there are also a lot more (10 times? 100 times?) as many kids walking around as on a normal night (drivers are also aware of this and are probably taking extra precautions).

Tradeoffs are hard. In the late 1960s and 1970s, there were about 2,000 kids (aged 5-14) either walking or riding bikes killed by motor vehicles per year. In recent years, it’s under 100 deaths per year (and the population size is similar: around 40 million kids). The meme below stated that worst thing that could happen to kids from going outside is getting eaten by a bear.

Either a bear eats you, or a car hits you pic.twitter.com/ZEmN3VSI2o

— Jeremy 'adjusted for inflation' Horpedahl 📈 (@jmhorp) October 16, 2023

The ironic thing is that’s much closer to true today than it was in the 1970s, when that photo was probably taken (bear attacks are still rare — only about 10 kids per year are killed by mammals, and that includes dogs). But should parents today return to the 1970s norm of letting kids ride outside, by themselves, without helmets? Would it mean that deaths would return to the 1970s levels? The answer to the last question is probably No — lots of other things (helmets, bike paths, cameras in cars) make bike riding and walking safer today.

But deaths would probably go up to some extent. Is this worth the tradeoff? It’s hard to say exactly what the tradeoffs are. Some have suggested that the decades-long decline in child mental health is partially caused by a decline in independent activity. Imagine that’s true. How much would child mental health need to improve for use to say the extra car accident deaths (how many?) are worth it?

Trade-offs are harder than we think sometimes. At the margin, kids probably should spend more time outside, and the overall risk of death is still very, very low. Still, it is worth considering if a culture where kids are encouraged to spend a lot more time outside is worth the trade-off.