Where Does Data Come From?

Emily Oster

12 min Read Emily Oster

Emily Oster

Where Does Data Come From?

Weight and weighting

Emily Oster

12 min Read

I teach a lot of classes on data, to a lot of different audiences: college students, graduate students, businesspeople, people who find me through the newsletter or Instagram. Once, I taught a data class to a middle-school assembly. My favorite way to start these classes — an opening that I’ve used with all of these audiences — is this:

Here is a fact from the CDC: In 2017-2018, 42.7% of Americans were obese. And here is my question: How do they know?

This is a simple question, and one that many people have a knee-jerk reaction to: “They weighed people.” But of course, it’s not that simple. They do weigh people. But which people? And who does the weighing? And how do you go from weighing some people to a statement about all Americans?

Today I want to unpack the answers to these questions, a bit like the way I would in class. Understanding the answers here is a lens into thinking more generally about where data comes from, and whether we can be confident in what it tells us.

Important note: I’m using obesity rate throughout today’s post because it is a number that is often cited in policy discussions, and it’s a good illustration of general principles. There are many good arguments for why BMI-based measures like this do not reflect a person’s health and why we should move away from a focus on them. (For more, I highly recommend Virginia Sole-Smith — we’ll be discussing her upcoming book, Fat Talk: Parenting in the Age of Diet Culture, in the newsletter early next year.) I’m using this example to talk about analytic concepts, not because there’s great value in the data itself. 

The data source

Let’s start by asking what the ideal way to measure this would be, from a data standpoint. If you wanted to know the exact right number at all times, you’d want to basically force everyone to weigh themselves every day and have that data be uploaded to some government server. From this, we’d be able to precisely calculate the share of people at any particular weight. Data-wise, great. In all other ways, terrifying and horrible. It’s not The Handmaid’s Tale over here (yet), so that’s not the way this is done.

Slightly more realistically, there are a number of existing data sources for this information. A large-scale example is anonymized medical records, which would provide weight from yearly check-ups. Apps are another possibility. People who use a fitness or diet tracker may enter their weight as part of that; certain diet trackers will link electronically to a scale, so this information is entered automatically. Some states will collect your weight when you apply for or renew a driver’s license.

In principle, these may seem like a good way to measure America’s weight. They’re easily accessible, in the sense that the information doesn’t have to be collected anew, and possibly cover many, many people. However: there are significant issues with these sources. One is that, in some cases, they rely on self-reports, which may not be accurate. A more pernicious issue is that all of these samples are selected in various ways. That is to say: none are representative of the full U.S. population.

This lack of representativeness is obvious if we think about dieters or the wearers of fitness trackers. But even a population of medical records — while better — may not be representative. People who are engaged with their health such that they go to the doctor for well visits are, at least in some ways, different from those who do not. Using only that population, we’ll get a biased estimate of what we want to know.

In order to make a statement like the one that I attributed to the CDC above, we need to have data from a representative sample of Americans — the simplest way to think about this is a random sample. It is important to say that we do not need to sample all Americans. One of the wondrous, magic things about statistics and sampling is that we can sample a subset of people — even quite a small share — and make statements about the whole population. These statements will come with some possible error, but we can quantify that error. But this is only possible if our sample is representative of the whole population.

The way the CDC actually gets these data on obesity (and on much other health data) is with a survey called the National Health and Nutrition Examination Survey (NHANES). The NHANES survey began in the 1960s and has run in more or less its current form since 1999. It includes roughly 5,000 individuals each year, and it’s run continuously with data released every two years.

The NHANES has two components. There is a survey component, which asks questions about demographics (race, income, education), health conditions, and diet. This is the source for a lot of data on American dietary patterns; participants do a one- or two-day “dietary recall” in which they list everything they ate during those days. We also get detailed information about any existing health conditions, and health behaviors.

The second component is the examination. This consists of a series of measurements, including medical and dental tests and laboratory tests. It is in this survey segment that information is collected on weight, along with blood pressure, laboratory measurements like triglycerides, and so on. This examination portion of the survey is done by NHANES survey people in a series of carefully designed mobile examination units.

The NHANES is designed as a representative sample. In an ideal world, the way we’d do that is to randomly choose 5,000 people from the American population of 300 million and survey them. This is infeasible with a study like this for many reasons, most notably that you’d need to get your mobile examination units all over the country. Instead, what the survey does is choose 15 random counties each year and then choose random households from within these counties, and then random people within those households. This approach allows the researchers to have the mobile units in a smaller number of locations. It also allows them to advertise the existence of the survey and to let people know what is going on.

Again, it might seem like magic, but actually this approach to sampling — when done randomly — will give you a representative sample that you can use to reflect the U.S. population. Statistics is cool! That magic, though, happens when you are able to actually survey and examine everyone you sample. That is: the survey picks a set of people within each county, and the ability to draw conclusions based on that subset of the population is reliant on them actually surveying and examining those people they picked.

The main issue with this is non-response. Not everyone you contact wants to be surveyed, and even fewer people want to be weighed and have their blood drawn. It takes time, and also can be invasive. In the data, about half of the people contacted are willing to be surveyed, and slightly fewer are willing to undergo the examination. If the refusal was random, this would be okay — you’d need to start with twice as many people, but you’d still do all right on being representative. The problem is that refusal is not random.

For example: Likely due to long-standing issues of mistreatment by the medical system, Black individuals are less likely to opt into the survey than those of other races. More-educated individuals are more likely to agree to be surveyed, on average, as are richer people. This means that the sample that you get is not random, and the data cannot simply be used as it is. The NHANES approaches (say) 10,000 people to get 5,000 responses; but even though the 10,000 people were randomly selected, the 5,000 are not.

At the end of the NHANES process, there is a data set of 5,000 individuals. On average, there are more white people in the sample than in the overall population, and more people with more education (among other imbalances). Reporting the obesity rate in the observed data would not be representative of the overall population.

So… what do you do?

Reweighting data

The short answer is that you “reweight” the data. Imagine that your data is on 10 people: 9 white people and 1 Black person. But your overall population has 7 white people and 3 Black people. If you want your data to represent your population in terms of race, you need to count your one Black person three times and each of your white people only 7/9ths of a time. In doing this, you are giving more weight to the person representing the group you do not have enough of and less weight to the people who you have too many of.

This reweighting can get very complicated when the sample is imbalanced in a lot of ways, as it is in the NHANES. Typically, the way it is done is by grouping people based on a set of characteristics (e.g. 20-to-39-year-old non-Hispanic white women living in urban areas with an intermediate median income) and then asking how the share of the people in the survey with that set of characteristics compares with the share of the overall U.S. population. Participants in this group are then assigned a survey weight, which tells researchers whether to up- or down-weight them in any overall statistics.

There are two important subtleties to this. The first is that in order to do this, you need a good number of people in each group. If there is literally one Black person in your entire sample, you cannot count them for the entire Black population of the U.S. One implication of this is that a survey like the NHANES starts out by “oversampling” smaller population groups, to make sure they have enough people to do their weighting.

A second issue, more pernicious, is that you can only weight based on things you see. This was brought home to me by a reader email, which was about a survey in the U.K. but has a similar feel:

I’ve just signed up for the U.K. future health study: 

I live in an ethnically diverse city with significant areas of deprivation.

However, at the initial screening I was struck by how similar the cohort was, mostly white middle-aged professionals who worked in The City (or at least had a job where they could get time off to attend). I’d say 75%+ had a Garmin [fitness watch] or equivalent, and we were all quite excited to get a free cholesterol check.

Some of the issues this person identifies (imbalances in race or age) are things we can deal with using the weighting procedures described. But some of these features — like Garmin ownership — are not things we measure, and therefore not things we can base our weights on.

The bottom line is that if the non-response to a survey like the NHANES is in part a function of unobservable differences across people (which it surely is), then we retain concerns about lack of representativeness. It can be difficult to know how important this is in magnitude, or even in what direction it biases our conclusions. We can sometimes speculate, but we cannot be sure.

I wish I could tell you that there is a good way to address these problems! It’s a topic I’ve studied in my academic work (see “A simple approximation for evaluating external validity bias,” written with the incomparable Isaiah Andrews), but we do not come up with any airtight solutions. The fundamental problem is that if your sample is selected based on features you cannot see — unobservables — then you’re kind of out of luck for making precise conclusions.

Summary and other contexts

When we want to make statements about characteristics of whole populations, be they the entire U.S. or something smaller, or larger, we must use representative samples. If my goal was to get the weight of 5,000 people, there are much simpler ways to collect that data than mobile clinics across the U.S. I could weigh people at the New York City Marathon, or people who go to a Packers game. But those approaches will yield a biased sample.

Yet even when we do our very, very best to sample in a representative way, we still run into problems if not everyone responds (and they do not!). We can up-weight and down-weight, and even when we do that, we are still not usually all the way there. It’s better than the Packers game! Not perfect, though.

The issues here come up all the time if you’re looking for them. Political polling, for example. Pollsters randomly sample people to call, but they definitely do not get a random sample of people answering them. There are many reweighting approaches to addressing these imbalances, but they do all run into the problem of unobservable selection (also, lying, but that’s for another day).

It is worth looking for these issues. We spend a lot of time, in this newsletter and in media in general, talking about issues like correlation versus causation. Those are important! But the more mundane question of where data comes from, and what it really measures — this is crucially important too.

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We are better writers than influencers, I promise. Thanks to our kids for filming our unboxing videos. People make this look way too easy. 

Only two weeks until our book “The Unexpected” is here! Preorder at the link in my bio. 💙

We are better writers than influencers, I promise. Thanks to our kids for filming our unboxing videos. People make this look way too easy.

Only two weeks until our book “The Unexpected” is here! Preorder at the link in my bio. 💙
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Exciting news! We have new, high-quality data that says it’s safe to take Tylenol during pregnancy and there is no link between Tylenol exposure and neurodevelopmental issues in kids. Comment “Link” for a DM to an article exploring this groundbreaking study.

While doctors have long said Tylenol was safe, confusing studies, panic headlines, and even a lawsuit have continually stoked fears in parents. As a result, many pregnant women have chosen not to take it, even if it would help them.

This is why good data is so important! When we can trust the data, we can trust our choices. And this study shows there is no blame to be placed on pregnant women here. So if you have a migraine or fever, please take your Tylenol.

#tylenol #pregnancy #pregnancyhealth #pregnancytips #parentdata #emilyoster

Exciting news! We have new, high-quality data that says it’s safe to take Tylenol during pregnancy and there is no link between Tylenol exposure and neurodevelopmental issues in kids. Comment “Link” for a DM to an article exploring this groundbreaking study.

While doctors have long said Tylenol was safe, confusing studies, panic headlines, and even a lawsuit have continually stoked fears in parents. As a result, many pregnant women have chosen not to take it, even if it would help them.

This is why good data is so important! When we can trust the data, we can trust our choices. And this study shows there is no blame to be placed on pregnant women here. So if you have a migraine or fever, please take your Tylenol.

#tylenol #pregnancy #pregnancyhealth #pregnancytips #parentdata #emilyoster
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How many words should kids say — and when? Comment “Link” for a DM to an article about language development!

For this graph, researchers used a standardized measure of vocabulary size. Parents were given a survey and checked off all the words and sentences they have heard their child say.

They found that the average child—the 50th percentile line—at 24 months has about 300 words. A child at the 10th percentile—near the bottom of the distribution—has only about 50 words. On the other end, a child at the 90th percentile has close to 600 words. One main takeaway from these graphs is the explosion of language after fourteen or sixteen months. 

What’s valuable about this data is it can give us something beyond a general guideline about when to consider early intervention, and also provide reassurance that there is a significant range in this distribution at all young ages. 

#cribsheet #emilyoster #parentdata #languagedevelopment #firstwords

How many words should kids say — and when? Comment “Link” for a DM to an article about language development!

For this graph, researchers used a standardized measure of vocabulary size. Parents were given a survey and checked off all the words and sentences they have heard their child say.

They found that the average child—the 50th percentile line—at 24 months has about 300 words. A child at the 10th percentile—near the bottom of the distribution—has only about 50 words. On the other end, a child at the 90th percentile has close to 600 words. One main takeaway from these graphs is the explosion of language after fourteen or sixteen months.

What’s valuable about this data is it can give us something beyond a general guideline about when to consider early intervention, and also provide reassurance that there is a significant range in this distribution at all young ages.

#cribsheet #emilyoster #parentdata #languagedevelopment #firstwords
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I saw this and literally laughed out loud 😂 Thank you @adamgrant for sharing this gem! Someone let me know who originally created this masterpiece so I can give them the proper credit.

I saw this and literally laughed out loud 😂 Thank you @adamgrant for sharing this gem! Someone let me know who originally created this masterpiece so I can give them the proper credit. ...

Perimenopause comes with a whole host of symptoms, like brain fog, low sex drive, poor energy, and loss of muscle mass. These symptoms can be extremely bothersome and hard to treat. Could testosterone help? Comment “Link” for a DM to an article about the data on testosterone treatment for women in perimenopause.

#perimenopause #perimenopausehealth #womenshealth #hormoneimbalance #emilyoster #parentdata

Perimenopause comes with a whole host of symptoms, like brain fog, low sex drive, poor energy, and loss of muscle mass. These symptoms can be extremely bothersome and hard to treat. Could testosterone help? Comment “Link” for a DM to an article about the data on testosterone treatment for women in perimenopause.

#perimenopause #perimenopausehealth #womenshealth #hormoneimbalance #emilyoster #parentdata
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What age is best to start swim lessons? Comment “Link” for a DM to an article about water safety for children 💦

Summer is quickly approaching! You might be wondering if it’s the right time to have your kid start swim lessons. The AAP recommends starting between 1 and 4 years old. This is largely based on a randomized trial where young children were put into 8 or 12 weeks of swim lessons. They found that swimming ability and water safety reactions improve in both groups, and more so in the 12 weeks group.

Below this age range though, they are too young to actually learn how to swim. It’s fine to bring your baby into the pool (if you’re holding them) and they might like the water. But starting formal safety-oriented swim lessons before this age isn’t likely to be very helpful.

Most importantly, no matter how old your kid is or how good of a swimmer they are, adult supervision is always necessary!

#swimlessons #watersafety #kidsswimminglessons #poolsafety #emilyoster #parentdata

What age is best to start swim lessons? Comment “Link” for a DM to an article about water safety for children 💦

Summer is quickly approaching! You might be wondering if it’s the right time to have your kid start swim lessons. The AAP recommends starting between 1 and 4 years old. This is largely based on a randomized trial where young children were put into 8 or 12 weeks of swim lessons. They found that swimming ability and water safety reactions improve in both groups, and more so in the 12 weeks group.

Below this age range though, they are too young to actually learn how to swim. It’s fine to bring your baby into the pool (if you’re holding them) and they might like the water. But starting formal safety-oriented swim lessons before this age isn’t likely to be very helpful.

Most importantly, no matter how old your kid is or how good of a swimmer they are, adult supervision is always necessary!

#swimlessons #watersafety #kidsswimminglessons #poolsafety #emilyoster #parentdata
...

Can babies have salt? 🧂 While babies don’t need extra salt beyond what’s in breast milk or formula, the risks of salt toxicity from normal foods are minimal. There are concerns about higher blood pressure in the long term due to a higher salt diet in the first year, but the data on these is not super compelling and the differences are small.

Like with most things, moderation is key! Avoid very salty chips or olives or saltines with your infant. But if you’re doing baby-led weaning, it’s okay for them to share your lightly salted meals. Your baby does not need their own, unsalted, chicken if you’re making yourself a roast. Just skip the super salty stuff.

 #emilyoster #parentdata #childnutrition #babynutrition #foodforkids

Can babies have salt? 🧂 While babies don’t need extra salt beyond what’s in breast milk or formula, the risks of salt toxicity from normal foods are minimal. There are concerns about higher blood pressure in the long term due to a higher salt diet in the first year, but the data on these is not super compelling and the differences are small.

Like with most things, moderation is key! Avoid very salty chips or olives or saltines with your infant. But if you’re doing baby-led weaning, it’s okay for them to share your lightly salted meals. Your baby does not need their own, unsalted, chicken if you’re making yourself a roast. Just skip the super salty stuff.

#emilyoster #parentdata #childnutrition #babynutrition #foodforkids
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Is sleep training bad? Comment “Link” for a DM to an article breaking down the data on sleep training 😴

Among parenting topics, sleep training is one of the most divisive. Ultimately, it’s important to know that studies looking at the short- and long-term effects of sleep training show no evidence of harm. The data actually shows it can improve infant sleep and lower parental depression.

Even so, while sleep training can be a great option, it will not be for everyone. Just as people can feel judged for sleep training, they can feel judged for not doing it. Engaging in any parenting behavior because it’s what’s expected of you is not a good idea. You have to do what works best for your family! If that’s sleep training, make a plan and implement it. If not, that’s okay too.

What’s your experience with sleep training? Did you feel judged for your decision to do (or not do) it?

#sleeptraining #newparents #babysleep #emilyoster #parentdata

Is sleep training bad? Comment “Link” for a DM to an article breaking down the data on sleep training 😴

Among parenting topics, sleep training is one of the most divisive. Ultimately, it’s important to know that studies looking at the short- and long-term effects of sleep training show no evidence of harm. The data actually shows it can improve infant sleep and lower parental depression.

Even so, while sleep training can be a great option, it will not be for everyone. Just as people can feel judged for sleep training, they can feel judged for not doing it. Engaging in any parenting behavior because it’s what’s expected of you is not a good idea. You have to do what works best for your family! If that’s sleep training, make a plan and implement it. If not, that’s okay too.

What’s your experience with sleep training? Did you feel judged for your decision to do (or not do) it?

#sleeptraining #newparents #babysleep #emilyoster #parentdata
...

Does your kid love to stall right before bedtime? 💤 Tell me more about their tactics in the comments below!

#funnytweets #bedtime #nightimeroutine #parentinghumor #parentingmemes

Does your kid love to stall right before bedtime? 💤 Tell me more about their tactics in the comments below!

#funnytweets #bedtime #nightimeroutine #parentinghumor #parentingmemes
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Got a big decision to make? 🤔 Comment “Link” for a DM to read about my easy mantra for making hard choices. 

When we face a complicated problem in pregnancy or parenting, and don’t like either option A or B, we often wait around for a secret third option to reveal itself. This magical thinking, as appealing as it is, gets in the way. We need a way to remind ourselves that we need to make an active choice, even if it is hard. The mantra I use for this: “There is no secret option C.”

Having this realization, accepting it, reminding ourselves of it, can help us make the hard decisions and accurately weigh the risks and benefits of our choices.

#parentingquotes #decisionmaking #nosecretoptionc #parentingadvice #emilyoster #parentdata

Got a big decision to make? 🤔 Comment “Link” for a DM to read about my easy mantra for making hard choices.

When we face a complicated problem in pregnancy or parenting, and don’t like either option A or B, we often wait around for a secret third option to reveal itself. This magical thinking, as appealing as it is, gets in the way. We need a way to remind ourselves that we need to make an active choice, even if it is hard. The mantra I use for this: “There is no secret option C.”

Having this realization, accepting it, reminding ourselves of it, can help us make the hard decisions and accurately weigh the risks and benefits of our choices.

#parentingquotes #decisionmaking #nosecretoptionc #parentingadvice #emilyoster #parentdata
...

Excuse the language, but I have such strong feelings about this subject! Sometimes, it feels like there’s no winning as a mother. People pressure you to breastfeed and, in the same breath, shame you for doing it in public. Which is it?!

So yes, they’re being completely unreasonable. You should be able to feed your baby in peace. What are some responses you can give to someone who tells you to cover up? Share in the comments below ⬇️

#breastfeeding #breastfeedinginpublic #breastfeedingmom #motherhood #emilyoster

Excuse the language, but I have such strong feelings about this subject! Sometimes, it feels like there’s no winning as a mother. People pressure you to breastfeed and, in the same breath, shame you for doing it in public. Which is it?!

So yes, they’re being completely unreasonable. You should be able to feed your baby in peace. What are some responses you can give to someone who tells you to cover up? Share in the comments below ⬇️

#breastfeeding #breastfeedinginpublic #breastfeedingmom #motherhood #emilyoster
...

Potty training can feel like a Mount Everest-size challenge, and sadly, our evidence-based guidance is poor. So, I created a survey to collate advice and feedback on success from about 6,000 participants.

How long does potty training take? We found that there is a strong basic pattern here: the later you wait to start, the shorter time it takes to potty train. On average, people who start at under 18 months report it takes them about 12 weeks for their child to be fully trained (using the toilet consistently for both peeing and pooping). For those who start between 3 and 3.5, it’s more like nine days. Keep in mind that for all of these age groups, there is a range of length of time from a few days to over a year. Sometimes parents are told that if you do it right, it only takes a few days. While that is true for some people, it is definitely not the norm.

If you’re in the throes of potty training, hang in there! 

#emilyoster #parentdata #pottytraining #pottytrainingtips #toddlerlife

Potty training can feel like a Mount Everest-size challenge, and sadly, our evidence-based guidance is poor. So, I created a survey to collate advice and feedback on success from about 6,000 participants.

How long does potty training take? We found that there is a strong basic pattern here: the later you wait to start, the shorter time it takes to potty train. On average, people who start at under 18 months report it takes them about 12 weeks for their child to be fully trained (using the toilet consistently for both peeing and pooping). For those who start between 3 and 3.5, it’s more like nine days. Keep in mind that for all of these age groups, there is a range of length of time from a few days to over a year. Sometimes parents are told that if you do it right, it only takes a few days. While that is true for some people, it is definitely not the norm.

If you’re in the throes of potty training, hang in there!

#emilyoster #parentdata #pottytraining #pottytrainingtips #toddlerlife
...

For children or adults with severe food allergies, they can be incredibly scary and restrictive. We may imagine that it’s easy to deal with a peanut allergy by, say, not eating peanut butter sandwiches. But for someone with a severe version of this allergy, they may never be able to go to a restaurant, for fear of a severe reaction to something in the air. Right now, there’s only one approved treatment for severe allergies like this and it’s limited to peanuts.

This is why the new medication Xolair is very exciting. It promises a second possible treatment avenue and one that works for other allergens. A new trail analyzed data from 177 children with severe food allergies. Two-thirds of the treatment group were able to tolerate the specified endpoint, versus just 7% of the placebo group. This is a very large treatment effect, and the authors found similarly large impacts on other allergens. 

There are some caveats: This treatment won’t work for everyone. (One-third of participants did not respond to it.) Additionally, this treatment is an injection given every two to four weeks, indefinitely. This may make it less palatable to children. 

Overall, even with caveats, this is life-changing news for many families!

#xolair #foodallergies #allergies #peanutallergy #emilyoster #parentdata

For children or adults with severe food allergies, they can be incredibly scary and restrictive. We may imagine that it’s easy to deal with a peanut allergy by, say, not eating peanut butter sandwiches. But for someone with a severe version of this allergy, they may never be able to go to a restaurant, for fear of a severe reaction to something in the air. Right now, there’s only one approved treatment for severe allergies like this and it’s limited to peanuts.

This is why the new medication Xolair is very exciting. It promises a second possible treatment avenue and one that works for other allergens. A new trail analyzed data from 177 children with severe food allergies. Two-thirds of the treatment group were able to tolerate the specified endpoint, versus just 7% of the placebo group. This is a very large treatment effect, and the authors found similarly large impacts on other allergens.

There are some caveats: This treatment won’t work for everyone. (One-third of participants did not respond to it.) Additionally, this treatment is an injection given every two to four weeks, indefinitely. This may make it less palatable to children.

Overall, even with caveats, this is life-changing news for many families!

#xolair #foodallergies #allergies #peanutallergy #emilyoster #parentdata
...

If you have a fever during pregnancy, you should take Tylenol, both because it will make you feel better and because of concerns about fever in pregnancy (although these are also overstated).

The evidence that suggests risks to Tylenol focuses largely on more extensive exposure — say, taking it for more than 28 days during pregnancy. There is no credible evidence, even correlational, to suggest that taking it occasionally for a fever or headache would be an issue.

People take Tylenol for a reason. For many people, the choice may be between debilitating weekly migraines and regular Tylenol usage. The impacts studies suggest are very small. In making this decision, we should weigh the real, known benefit against the suggestion of this possible risk. Perhaps not everyone will come out at the same place on this, but it is crucial we give people the tools to make the choice for themselves.

#emilyoster #parentdata #tylenol #pregnancy #pregnancytips

If you have a fever during pregnancy, you should take Tylenol, both because it will make you feel better and because of concerns about fever in pregnancy (although these are also overstated).

The evidence that suggests risks to Tylenol focuses largely on more extensive exposure — say, taking it for more than 28 days during pregnancy. There is no credible evidence, even correlational, to suggest that taking it occasionally for a fever or headache would be an issue.

People take Tylenol for a reason. For many people, the choice may be between debilitating weekly migraines and regular Tylenol usage. The impacts studies suggest are very small. In making this decision, we should weigh the real, known benefit against the suggestion of this possible risk. Perhaps not everyone will come out at the same place on this, but it is crucial we give people the tools to make the choice for themselves.

#emilyoster #parentdata #tylenol #pregnancy #pregnancytips
...

Parenting trends are like Cabbage Patch Kids: they’re usually only popular because a bunch of people are using them! Most of the time, these trends are not based on new scientific research, and even if they are, that new research doesn’t reflect all of what we’ve studied before.

In the future, before hopping onto the latest trend, check the data first. Unlike Cabbage Patch Kids, parenting trends can add a lot of unnecessary stress and challenges to your plate. What’s a recent trend that you’ve been wondering about?

#parentdata #emilyoster #parentingtips #parentingadvice #parentinghacks

Parenting trends are like Cabbage Patch Kids: they’re usually only popular because a bunch of people are using them! Most of the time, these trends are not based on new scientific research, and even if they are, that new research doesn’t reflect all of what we’ve studied before.

In the future, before hopping onto the latest trend, check the data first. Unlike Cabbage Patch Kids, parenting trends can add a lot of unnecessary stress and challenges to your plate. What’s a recent trend that you’ve been wondering about?

#parentdata #emilyoster #parentingtips #parentingadvice #parentinghacks
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As of this week, 1 million copies of my books have been sold. This feels humbling and, frankly, unbelievable. I’m so thankful to those of you who’ve read and passed along your recommendations of the books.

When I wrote Expecting Better, I had no plan for all of this — I wrote that book because I felt compelled to write it, because it was the book I wanted to read. As I’ve come out with more books, and now ParentData, I am closer to seeing what I hope we can all create. That is: a world where everyone has access to reliable data, based on causal evidence, to make informed, confident decisions that work for their families.

I’m so grateful you’re all here as a part of this, and I want to thank you! If you’ve been waiting for the right moment to sign up for full access to ParentData, this is it. ⭐️ Comment “Link” for a DM with a discount code for 20% off of a new monthly or annual subscription to ParentData! 

Thank you again for being the best community of readers and internet-friends on the planet. I am so lucky to have you all here.

#parentdata #emilyoster #expectingbetter #cribsheet #familyfirm #parentingcommunity

As of this week, 1 million copies of my books have been sold. This feels humbling and, frankly, unbelievable. I’m so thankful to those of you who’ve read and passed along your recommendations of the books.

When I wrote Expecting Better, I had no plan for all of this — I wrote that book because I felt compelled to write it, because it was the book I wanted to read. As I’ve come out with more books, and now ParentData, I am closer to seeing what I hope we can all create. That is: a world where everyone has access to reliable data, based on causal evidence, to make informed, confident decisions that work for their families.

I’m so grateful you’re all here as a part of this, and I want to thank you! If you’ve been waiting for the right moment to sign up for full access to ParentData, this is it. ⭐️ Comment “Link” for a DM with a discount code for 20% off of a new monthly or annual subscription to ParentData!

Thank you again for being the best community of readers and internet-friends on the planet. I am so lucky to have you all here.

#parentdata #emilyoster #expectingbetter #cribsheet #familyfirm #parentingcommunity
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Just eat your Cheerios and move on.

Just eat your Cheerios and move on. ...

The AAP’s guidelines recommend sleeping in the same room as your baby “ideally for the first six months.” However, the risk of SIDS is dramatically lower after four months, and the evidence in favor of the protective effect of room sharing is quite weak (both overall and even more so after four months). There is also growing evidence that infants who sleep in their own room by four months sleep better at four months, better at nine months, and even better at 30 months.

With this in mind, it’s worth asking why this recommendation continues at all — or at least why the AAP doesn’t push it back to four months. They say decreased arousals from sleep are linked to SIDS, which could mean that babies sleeping in their own room is risky. But this link is extremely indirect, and they do not show direct evidence to support it.

According to the data we have, parents should sleep in the same room as a baby for as long as it works for them! Sharing a room with a child may have negative impacts on both child and adult sleep. We should give families more help in navigating these trade-offs and making the decisions that work best for them.

#emilyoster #parentdata #roomsharing #sids #parentingguide

The AAP’s guidelines recommend sleeping in the same room as your baby “ideally for the first six months.” However, the risk of SIDS is dramatically lower after four months, and the evidence in favor of the protective effect of room sharing is quite weak (both overall and even more so after four months). There is also growing evidence that infants who sleep in their own room by four months sleep better at four months, better at nine months, and even better at 30 months.

With this in mind, it’s worth asking why this recommendation continues at all — or at least why the AAP doesn’t push it back to four months. They say decreased arousals from sleep are linked to SIDS, which could mean that babies sleeping in their own room is risky. But this link is extremely indirect, and they do not show direct evidence to support it.

According to the data we have, parents should sleep in the same room as a baby for as long as it works for them! Sharing a room with a child may have negative impacts on both child and adult sleep. We should give families more help in navigating these trade-offs and making the decisions that work best for them.

#emilyoster #parentdata #roomsharing #sids #parentingguide
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