Bayes’ Rule Is My Faves Rule

Emily Oster

10 min Read Emily Oster

Emily Oster

Bayes’ Rule Is My Faves Rule

Nerding out. Just nerding out all over the place.

Emily Oster

10 min Read

I get a lot of questions from you all. Which I completely adore, even if I cannot answer them all. But I’m consistently reminded that everyone’s questions are slightly different, which reminds me of the value of articulating broader approaches.

Approaches to decision making are one part of this, but there’s also the question of how to incorporate new data into your analysis of the overall picture. I realized that when people ask about this, I talk a lot about “context” and “overall context” and “contextualizing” and “reading in the context of what we already know”. In fact, though, what I mean is: “Use Bayes’ Rule”. So I thought a post which really dives into Bayes’ Rule would be…fun? Is fun the word for that? I think so.

Teaching example for Bayes’ Rule

I use this example all the time. I think I’ve discussed it in every class I teach, regardless of the topic. I sometimes incorporate it into book talks. Once, I asked it to a group of University Trustees (one person got it right).

Here it is:

Imagine you have a disease which affects 1 in 10,000 people. You’ve got a test which detects 99.9% of cases, with just a 2% false positive rate. Someone comes in and they get a positive test. What is the chance they have the disease?

When I give this question, usually people’s answers are in the range of 98%, 99%. Sometimes 95%. People are drawn to the idea that if this is a good test, which detects nearly all cases, then if you have a positive test result, you’re very likely to have it.

The true answer is that if you have a positive test result, your actual chance of having the disease is about 0.5%, or about 1 in 200. So, half of 1 percent. That is, even with a positive test result, you are not that likely to have the disease. (This is called the “posterior probability”).

Why is this?

The key is the false positive rate here, combined with the very low baseline risk. The easiest way to think about it (for me) is the following. Take a sample of 10,000 people. One of them has the disease (on average) and your test is very good — it will almost surely find that one person. 9,999 of them do not have the disease. The test has a 2% false positive rate, which means 2% of those people without the disease will be detected to have it. That’s about 200 people.

The result is that you have (approximately) 201 people who test positive. The one actual positive person, and 200 people who are really negative but where the test was wrong. Of the positive tests, that’s 0.5% who actually have the disease. What seems like — and is! — a small false positive rate amplifies because of the low baseline risk.

To be clear, it isn’t that this test isn’t useful. You’ve learned a huge amount from the positive test, since a risk of 1 in 200 is very different from 1 in 10,000. It’s just not 100%.

If you want a formal treatment of Bayes’ rule, Wikipedia is helpful. Here’s the quick math:

Bayes Rule Formula

What does Bayes’ rule do?

Help me understand this better.

This is a fun brain teaser, sure, but it also has implications for how we process new information, for what we learn from it.

Let’s take an example of caffeine in pregnancy. Imagine a new study comes out (an actual new study, with data, not like the one last week) showing that coffee in pregnancy causes miscarriage. Our hypothetical study shows caffeine increases miscarriage, with a result that is “statistically significant”.

How much should we learn from this? It’s going to depend on a few things, all of which go into our calculations above.

  • First: the “prior probability”. Before this study was revealed, what did the existing data say about the chance that caffeine causes miscarriage and how confident were we in it?
  • Second, the “false positive” rate. This relates to the significance in the paper. If a result is “significant at the 5% level” (i.e. with a p-value of 0.05) one (slightly loose) way to think of this is that there is a 5% false positive rate.
  • Third, the “true positive rate”. That is, if the effect is real, what is the chance this paper picks it up? For simplicity, I’m going to ignore this for now and just assume that if there is a real effect, we’d see it.

Let’s start with the importance of the prior probability. Imagine that coming into this study I was really, really sure — like 99.99% sure — that a small amount of caffeine does not cause miscarriage. And now there is a study with a 5% false positive rate, saying that caffeine does cause miscarriage. I do my fancy Bayes’ Rule calculation on that, and what I come out with is: after seeing these data, I am 99.8% sure that a small amount of caffeine doesn’t cause miscarriage. I’m still really, really confident in my original conclusion.

Why?

Basically, because I was so sure beforehand, the addition of this new data makes me a little bit more worried, but only a little bit.

We can contrast with someone who was unsure before — who maybe thought there was a 50% chance that caffeine is dangerous. For them, after they see these new data, they think the chance is 95%. This information moves their estimate a lot, simply because they knew less to begin with.

The second thing that matters is the false positive rate. What if the study were really, really big and really, really convincing — a randomized controlled trial with millions of women which concluded coffee was dangerous in pregnancy. Such a large study would probably have a very high level of significance, a very low “false positive” risk.

We can take the person who is 99.99% sure that caffeine is safe. If they encountered a study with a 0.01% false positive rate, their updated probability would be 50%. They’re still not fully convinced — their prior is so strong — but the more precise data, the lower false positive rate, gets much more weight with them. (For the person who started at 50%, after seeing this good study they’d be all the way at 99.99%).

I’ve framed this in terms of how convinced an individual is, but really I think you can read this as how convincing the baseline data is. When we are very, very sure about something, new evidence shouldn’t move us as much. When we are unsure, it moves us a lot. Similarly, the better the new evidence, the more it should move you. Yes, these points may seem obvious. But I’m not sure we always incorporate them into our thinking.

Where is Bayes’ Rule useful?

I literally use Bayes’ Rule all the time. But in terms of the topics I talk through here, a couple of examples…

New Studies

Much of what we all think about is how to interpret new studies, be they about parenting or pregnancy or, in this moment, COVID. I’ve talked and written a lot about being careful not to over-react to new studies. That’s really a pitch to use Bayes’ rule. When we see a new study, think about (a) what you knew before and (b) how informative this study is. What’s the “false positive” chance you assign to these findings?

When I looked at that new study on caffeine last week, I came into it with a strong prior (based on all of the other information we had) that some caffeine during pregnancy was safe. Combined with the fact that the study was bad (which we could frame as a “high false positive” rate), my updated probability was not very different, or not at all different.

A contrast is something like the ARRIVE trial, on 39 week induction, which I wrote more about here. Coming into reading that study, my sense was the question of whether inductions lead to C-sections was much less settled. The fact that the study was very good, was very convincing, moved my judgment about this link quite a lot.

And, of course, I use this all the time in studies on COVID-19, as I try to take each piece of new data (on kids, on schools, on transmission) and incorporate it in my thinking.

When you read a new study, read it through this lens: what’s your prior, and what’s the false positive rate?

Symptoms and Test Results

The basic observation is that if something is unlikely to begin with, symptoms or test results should be interpreted in that light. Headache is a classic example: if someone had a severe headache, you should not automatically jump to the fear they have a brain tumor (even though severe headache is common with tumors), since this is very, very rare and most serious headaches are not tumor-related.

The other place this comes up is in how we interpret medical information, including both symptoms and test results.

In pregnancy, this arises (for example) in thinking through genetic testing results. Fetal genetic screening has gotten better, but there are still false positives in many of our tests. If you are young, if your baseline risk is low, even a worrisome test result does not necessarily mean the chance of a problem is very high.

Similar things come up with kids. One of my children once failed a hearing test, necessitating a visit for a formal audiological exam. It was hard not to freak out (this is always hard for me) but Jesse pointed out that given everything else we knew (the kid in question talked all the time, had a good vocabulary, her teachers hadn’t complained about it) our prior probability of her having a hearing problem was very low. Given that the tests have high false positive rates, I should calm down. (It was fine).

And it would be remiss not to talk through COVID-19 testing. All of our COVID-19 tests have some false positive rates, including the common PCR nasal swabs. One of the issues which comes up as (for example) Universities do massive asymptomatic surveillance testing is that at least some people identified as COVID-19 cases will be false positives. In a population with low prevalence — which we hope will be the case in these universities — it may be the case that a lot of the positive tests are false positives. Even if you get a positive test result, the actual risk of having COVID-19 may still be low. (Don’t worry if you live around a college: nearly all of them are requiring people to quarantine with a positive test, even if it may be a false one).

Conclusion

Bayes’ Rule is the Best!

(Here is hoping I do not get a lot of emails from statisticians complaining about how I have not explained this in a way they like.)

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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
...

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
...

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
...

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
...

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
...

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
...

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
...

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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It was an absolute pleasure to be featured on the @tamronhallshow! We talked about all things data-driven parenting and, in this clip, what I call the plague of secret parenting. To balance having a career and having a family, we can’t hide the fact that we’re parents. If mothers and fathers at the top can speak more openly about child-care obligations, it will help us all set a new precedent.

Watch the full segment at the link in my bio 🔗

#tamronhall #tamronhallshow #emilyoster #parentingsupport #workingparents

It was an absolute pleasure to be featured on the @tamronhallshow! We talked about all things data-driven parenting and, in this clip, what I call the plague of secret parenting. To balance having a career and having a family, we can’t hide the fact that we’re parents. If mothers and fathers at the top can speak more openly about child-care obligations, it will help us all set a new precedent.

Watch the full segment at the link in my bio 🔗

#tamronhall #tamronhallshow #emilyoster #parentingsupport #workingparents
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Invisible labor. It’s the work — in our households especially — that has to happen but that no one sees. It’s making the doctor’s appointment, ensuring birthday cards are purchased, remembering the milk.

My guest on this episode, @everodsky, has come up with a solution here, or at least a way for us to recognize the problem and make our own solutions. I’ve wanted to speak with Eve for ages, since I read her book Fair Play. We had a great conversation about the division of household labor, one I think you’ll get a lot out of!

Listen and subscribe to ParentData with Emily Oster in your favorite podcast app 🎧

#emilyoster #parentdata #parentdatapodcast #parentingpodcast #householdtips #fairplay #invisiblelabor

Invisible labor. It’s the work — in our households especially — that has to happen but that no one sees. It’s making the doctor’s appointment, ensuring birthday cards are purchased, remembering the milk.

My guest on this episode, @everodsky, has come up with a solution here, or at least a way for us to recognize the problem and make our own solutions. I’ve wanted to speak with Eve for ages, since I read her book Fair Play. We had a great conversation about the division of household labor, one I think you’ll get a lot out of!

Listen and subscribe to ParentData with Emily Oster in your favorite podcast app 🎧

#emilyoster #parentdata #parentdatapodcast #parentingpodcast #householdtips #fairplay #invisiblelabor
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