by Emily Oster
Vaccination does a very good job of protecting against disease, but it is not perfect. For pertussis, for example, immunity wears off over time. Despite this, studies consistently show that even in places with a high overall vaccination rate, children who are vaccinated are less likely to become infected than those who are not.13 During a 2015 measles outbreak that originated in Disneyland, the affected children were largely those whose parents had not had them vaccinated.
If you are nervous about vaccines, despite the evidence above, there may be a temptation to rely on the actions of others to prevent your own child’s illness. This is the idea of “herd immunity”: if a large enough share of people are vaccinated, then a disease cannot get a foothold, and the whole population—the herd—is immune. And it is true that if your child is literally the only child who is not vaccinated in your area, and you never travel anywhere that there are other unvaccinated children, your child is pretty much guaranteed not to get these diseases.
But how feasible is that? For one thing, many areas of the US have vaccination rates that are below the rate needed for herd immunity: in some pockets, MMR vaccine rates are around 80 percent; you need a vaccination rate of at least 90 percent to have a hope of herd immunity. Pertussis is even more common and requires even higher vaccination rates to deliver herd immunity. As a result, about half the counties in the US have at least one pertussis case every year. Many have more. Even if you focus only on the risks to your child in particular, there are good reasons to vaccinate.
And it is worth saying that vaccination is pro-social. If everyone tried to do what economists call “free-ride” and not vaccinate their children, then we’d have no vaccination and a lot of disease. Some children cannot be vaccinated due to immune deficiencies, cancer, or other complications; healthy children getting vaccinated protects these vulnerable kids.
Most of us born in the past forty years have not known a time when the diseases for which we vaccinate our children were common. Maybe you’ve heard of one or two children getting measles, but they probably got better, since the vast majority of people recover from the disease. Most of us do not know anyone who died from a vaccine-preventable disease. But it can happen, and when these diseases are common, it does.
And it is worth remembering that people can have terrible reactions even to diseases that are mostly not that serious. We probably remember chicken pox as a pretty benign, if itchy, illness. But prior to the development of a vaccine, it caused about a hundred deaths and nine thousand hospitalizations a year. Pertussis deaths—ten to twenty a year—occur even now, mostly among babies who are too young to be vaccinated yet, and are therefore relying on other people’s vaccination behavior to protect them.
Particularly when you haven’t seen or experienced widespread illness, vaccines can seem like a waste of time—like you’re sticking needles into your kid for no reason. But the fact of the matter is, they are not. Vaccines prevent disease, suffering, and death.
DELAYED VACCINATION SCHEDULES
Some vaccine-anxious parents favor a delayed vaccine schedule, in which children receive vaccines spaced out over a longer period of time rather than being given several at once.
There is no reason to do this, given the evidence on vaccine safety that I outlined earlier, and in fact, the risk of a febrile seizure actually increases if the MMR vaccine is given later.14 Delaying vaccines will not help to avoid any of the limited adverse events attributed to vaccination. It also takes more of your time to visit the doctor repeatedly for shots, and your kid will not like them.
The only value I can see in a delayed vaccination schedule is that it may encourage some parents to vaccinate when they wouldn’t otherwise. Later is better than never, although in many cases—the rotavirus vaccines, for example—there are good reasons to start on time. The first hepatitis B vaccines are given in the first couple of days of a child’s life and, in the unlikely case of undiagnosed hepatitis B in the mother, can prevent long-term development of liver cancer in the child.15 So there are reasons to start on time.
Some doctors also worry that offering delayed vaccinations gives the impression that people should be nervous about vaccines, that there is something to worry about. Could that encourage fewer people to vaccinate? It is an interesting theory, but there is not much evidence to support it.
From an individual parent standpoint, the bottom line is that there is simply no reason for delay.
The Bottom Line
Vaccinations are safe.
A very small share of people have allergic reactions, which are treatable.
There are some extremely rare adverse events, most of which occur in immune-compromised children.
The only more common risks are fever and febrile seizures, which are also rare and do not do long-term harm.
There is no evidence of a link between vaccines and autism, and much evidence to refute such a link.
Vaccines prevent children from getting sick.
9
Stay-at-Home Mom? Stay-at-Work Mom?
Nothing in the Mommy Wars takes on as much weight as the choice to return to work or not. The title of this chapter comes from a friend whose son was once asked at school, “What kind of mom do you have? I have a stay-at-home mom,” to which my friend’s son responded, “Oh, I have a stay-at-work mom.”
The phrasing of this—what kind of mom do you have?—encapsulates much of the tension. Many of us have the feeling that the choice of what we do during the day is going to determine, at a deep level, what kind of mom (and person) we are.
Additionally, or perhaps as a result, this is an area with a tremendous amount of associated tension and unhappiness. Women who work (some of them, anyway) tell me they feel guilty about not being with their child every minute. Those who do not work (some of them, anyway) tell me they feel isolated and resentful at times. And even when we are happy with our choices at a personal level, it can feel as though there’s a lot of judgment coming from both directions:
“Why aren’t you available to go on the school field trip? Oh, I see, you’ll be at work. It’s too bad—Petunia was asking about you.”
“So what do you do? Oh, you’re just home with the kids? I could never do that—I’d let so many people down at work.”
People, this has got to stop. All cross-parental judgment is unhelpful and counterproductive, and this is no different.
For one thing, the whole premise of the discussion is gendered in an unhelpful way. The choice of whether to have a parent stay home is one your family will need to make. But why does it have to be Mom? It doesn’t. Framing this through the stay-at-home-mom lens makes it harder for people to think “stay-at-home dad” is a valid choice. But it should be. Never mind that sometimes a family has two moms. Or two dads. Or only one parent.
So let’s start by just framing this not as “What kind of mom will you be?” but “What is the optimal configuration of adult work hours for your household?” Less catchy, yes, but also perhaps more helpful for decision-making.
Second, this discussion ignores the fact that this really isn’t a choice for some families. There are plenty of people in the US who cannot get by—and by “get by” I mean have a place to live and put food on the table—without all the adults in the household working.
If your family is lucky enough to have a choice, the goal of this chapter is to try to give you a way to think about it. Ideally, this starts with decision theory and hard data, not with guilt and shame.
STRUCTURING THE DECISION
How should you think about the choice of working? I’d argue it has three components.
What is best for your child? (Let’s take “best” to mean likely to help promote their long-term life success, happiness, etc.)
What do you want to do?
What are the implications of yo
ur choice for the family budget?
People often talk about 1 and 3, and I’ll spend some time on those in this chapter. But I’d like to encourage you to also think about 2. That is, you should think about whether you want to work. It is common for people to say they work “because I have to” or stay home “because I have to.” And in either case, that can sometimes be true. But I think it is not true as much as people say it.
And this is a problem. It should be okay to say you made this choice because you wanted to work or wanted to stay home.
I’ll say it: I am lucky enough to not have to work, in the sense that Jesse and I could change how we organize our life to live on one income. I work because I like to. I love my kids! They are amazing. But I wouldn’t be happy staying home with them. I’ve figured out that my happiness-maximizing allocation is something like eight hours of work and three hours of kids a day.
It isn’t that I like my job more than my kids overall—if I had to pick, the kids would win every time. But the “marginal value” of time with my kids declines fast. In part, this is because kids are exhausting. The first hour with them is amazing, the second less good, and by hour four I’m ready for a glass of wine or, even better, some time with my research.
My job doesn’t have this feature. Yes, the eighth hour is less fun than the seventh, but the highs are not as high and the lows are not as low. The physical and emotional challenges of work pale in comparison to the physical and emotional challenges of being an on-scene parent. The eighth hour at my job is better than the fifth hour with the kids on a typical day. And that is why I have a job. Because I like it.
It should be okay to say this. Just like it should be okay to say that you stay home with your kids because that is what you want to do. I’m well aware that many people don’t want to be an economist for eight hours a day. We shouldn’t have to say we’re staying home for children’s optimal development, or at least, that shouldn’t be the only factor in the decision. “This is the lifestyle I prefer” or “This is what works for my family” are both okay reasons to make choices! So before you even get into reading what the evidence says is “best” for your child or thinking about the family budget, you—and your partner, or any other caregiving adults in the house—should think about what you would really like to do.
And then you can think about the data and the constraints.
I’m going to start by talking about the choice to work at all—first, its impacts on your child, and second, a bit about how to think about its impacts on your budget. At the end of the chapter, I’ll spend some time on the question of early parental leave and whether there is any guidance about how much leave to take if you do plan to return to work.
IMPACTS OF PARENTAL EMPLOYMENT ON CHILD OUTCOMES
Let’s start with the first question: Is it better (or worse) for your child’s development to have one parent stay home?
This is an extremely difficult question to answer. Why? First, households that choose to have a parent stay home are different from those that do not. And these differences, totally independent of a parent staying home or not, are likely to influence what happens to the children in those households.
Second, what your child does while you are at work is likely to matter tremendously. Once they are older, they’ll all go to school, but if we are talking about young kids, the outcomes will be influenced by whether they are in a good care environment (the next chapter will spend some time on how to think about childcare if you do choose to return to work).
Finally, working generally means money. And money also may be good for your family, or open up opportunities you and your children wouldn’t have otherwise. So it is a challenge to separate the impact of income from the impact of parental time.
Even with these caveats, we can dive into the data.
We can start with a place where we do have some causal evidence: the impact of a parent staying home in the first couple of years. I’ll talk below about maternity leave specifically, and the question of, say, no maternity leave versus six weeks or three months of leave. But there is also a set of literature that estimates whether it matters for kids if parents are home for, say, a year versus six months, or fifteen months versus a year. This comes from Europe and Canada, where policies have been introduced at various times to extend maternity leave into these ranges. (Let’s leave aside our anger that the US makes people fight for six weeks while these other places are arguing about one year versus two.)
In this literature, the authors are exploiting a change in a policy, not differences in choices, so they can be more confident about their conclusions. Extending maternity leave from six months to a year makes some women stay home for a year when they would otherwise have stayed home for six months. By comparing the outcomes of children who are born in the “six month” maternity leave policy to those born in the “year” policy, we can learn about the effects of maternity leave without worrying about underlying differences across parents.
The bottom line from this literature is that these parental-leave extensions have no effect on child outcomes.1 No effects on children’s test scores in school, on income later in life, or on anything else. In many cases, these studies have very long follow-up periods. We can say, for example, that one year of parental leave versus two years doesn’t influence a child’s high school test scores or earnings in early adulthood.
This evidence focuses on parents working in the first years. If we want to see the impact of parents working when their children are older, we are limited to studies that estimate correlations, not causal impacts. Some studies do exist, though, and when we look for evidence on schooling—test scores, school completion—these correlations tend to be about zero.2 Two parents working full time has a similar effect to one parent working and one not.
There is sometimes a bit of nuance in the results. One thing that is commonly seen is that children in families where one parent works part time and the other works full time tend to perform best in school—better than children whose parents both work full time or who have one parent who doesn’t work at all.3 This could be due to the working configuration, but I think it’s more likely due to differences between these families.4
Second, studies tend to find that the impacts of both parents working are positive (i.e., working is better) for kids from poorer families, and less positive (or even slightly negative) for children from richer families.5 The outcomes here are things like test scores, school achievement, and even obesity.
Researchers tend to interpret this as saying that in poor households, the income from working is important for child outcomes. Whereas in richer households, the lost time doing “enriching” things with a parent is more important. This is possible, although since these estimates are still just correlations, it is challenging to read so much into the data. And even if we do admit this interpretation, it highlights the importance of the child’s activities, not the parent leave configuration.
A final note is that some people have argued that if both parents work—and, specifically, if Mom works—their daughters are more likely to work in the long run and show less evidence of sex stereotypes.6 These are interesting ideas, and certainly it might be nice to think your kids are modeling themselves after you. But most of this data comes from comparing the US to Europe, so it is hard to know if the effects are attributable to maternal employment or other differences.
Tying this all together, my view is that the weight of the evidence suggests the net effects of working on child development are small or zero. Depending on your household configuration, these effects could be a little positive or a little negative. But this isn’t the decision that is going to make or break your child’s future success (if there is any decision that would at all).
PARENTAL LEAVE
The United States has subpar maternity leave policies. Many European countries give months—even a year or two—of paid, or partially paid, leave with gua
ranteed job security. Many people in the US have no paid leave at all, and even unpaid leave (say, through the Family Medical Leave Act, or FMLA) is typically capped at twelve weeks and is available to only about 60 percent of working people.
This has slowly started to change. Some states—notably California, New York, Rhode Island (shout-out!), New Jersey, Washington, and Washington, DC—have introduced paid-leave provisions. These benefits typically extend only six to twelve weeks, but they’re at least something. And there are discussions of paid leave at the federal level, although nothing has yet come of them.
If you are lucky, your job provides some paid leave. This could be up to three or four months, depending on where you work, or may be less. Technology firms have been working to set an example by providing up to four months of paid leave for women and men. Of course, you might not work at Facebook.
Parental leave appears to be beneficial. There is a growing body of evidence suggesting that babies do better when their mothers take some maternity leave. In the US, for example, research has shown that when the FMLA was introduced, babies did better. Premature birth went down, as did infant mortality.7 The mechanism may be that if moms are off work with small babies, they are better able to get care for them when they are sick. This policy may also have encouraged leave before birth for women with difficult pregnancies, which could account for the effect on premature birth.
