What is life expectancy? (video)

My YouTube career may have peaked in 2015, with the now-classic video, Total Fertility Rate, which has been viewed almost 30,000 times (124 likes!). Since then the technical quality has improved, but not the viewership.

Recently I heard someone say (sorry, I can’t remember who) that they were looking for a short video explaining what life expectancy is. This was after the CDC reported that US life expectancy in the first half of 2020 decreased by 1 year, which generated some confusion. Outside of secondary effects, the pandemic did reduce life “expectancy” for people it didn’t kill, and here we are (still alive, so far) reading about it, so how could our life expectancy have been affected? did last year’s deaths mean people would live less long in the future? I said somewhere on twitter than “life expectancy” is a bad name for this common statistic, and I think it is. I don’t have a better name for it, though, and it’s probably to late to change anyway.

So, to help meet the current need, and to try to reach my past video glory, yesterday I produced, “What is life expectancy?“, a 6-minute explainer, using 3 graphs, to help people understand. I didn’t discuss the recent COVID results so as not to date the video, and I hope it will be useful in the future (that it has a long life expectancy).

Here it is:

Pandemic Baby Bust situation update

[Update: California released revised birth numbers, which added a trivial number to previous months, except December, where they added a few thousand, so now the state has a 10% decline for the month, relative to 2019. I hadn’t seen a revision that large before.]

Lots of people are talking about falling birth rates — even more than they were before. First a data snapshot, then a link roundup.

For US states, we have numbers through December for Arizona, California, Florida, Hawaii, and Ohio. They are all showing substantial declines in birth rates from previous years. Most dramatically, California just posted December numbers, and revised the numbers from earlier months, now showing a 19% 10% drop in December. After adding about 500 births to November and a few to October, the drop in those two months is now 9%. The state’s overall drop for the year is now 6.2%. These are, to put it mildly, very larges declines in historical terms. Even if California adds 500 to December later, it will still be down 18%. Yikes. One thing we don’t yet know is how much of this is driven by people moving around, rather than just changes in birth rates. California in 2019 had more people leaving the state (before the pandemic) than before, and presumably there have been essentially no international immigrants in 2020. Hawaii also has some “birth tourism”, which probably didn’t happen in 2020, and has had a bad year for tourism generally. So much remains to be learned.

Here are the state trends (figure updated Feb 18):

births 18-20 state small multiple by month

From the few non-US places that I’m getting monthly data so far, the trend is not so dramatic. Although British Columbia posted a steep drop in December. I don’t know why I keep hoping Scotland will settle down their numbers… (updated Feb 18):

births countries 18-20 small multiple by month

Here are some recent items from elsewhere on this topic:

  • That led to some local TV, including this from KARE11 in Minneapolis:

Good news / bad news clarification

There’s an unfortunate piece of editing in the NBCLX piece, where I’m quoted like this: “Well, this is a bad situation. [cut] The declines we’re seeing now are pretty substantial.” To clarify — and I said this in the interview, but accidents happen — I am not saying the decline in births is a bad situation, I’m saying the pandemic is a bad situation, which is causing a decline in births. Unfortunately, this has slipped. As when the Independent quoted the piece (without talking to me) and said, “Speaking to the outlet, Philip Cohen, a sociologist and demographer at the University of Maryland, called the decline a ‘bad situation’.”

The data for this project is available here: osf.io/pvz3g/. You’re free to use it.

For more on fertility decline, including whether it’s good or bad, and where it might be going, follow the fertility tag.

Acknowledgement: We have lots of good conversation about this on Twitter, where there is great demography going on. Also, Lisa Carlson, a graduate student at Bowling Green State University, who works in the National Center for Family and Marriage Research, pointed me toward some of this state data, which I appreciate.

The pandemic and the family, demography edition (video)

I think the big demographic story of 2021 is likely to be the very large decline in births. I think everything points that way and I think it’s going to be quite shocking when we see how big it is. — Philip Cohen, October 27, 2020

I gave a talk yesterday at the University of California, Irvine Center for Demographic and Social Analysis. The slides are here under CC-BY license. The video is below.

After reviewing the state of the economic and social shock of the pandemic, with implications for family processes and events (sex, contraception, pregnancy, birth, marriage, and divorce), I presented some new information on births and marriage.

Here is the data on births, in Florida and California, the only states I found that have monthly updated birth numbers through September (subject to revision, but probably not by much). Both show large declines in births in 2020. Which seems hard to link to the pandemic, gestation times being what they are (but maybe more reasonable than last month’s report). There may already be more miscarriages and abortions, or maybe fewer premature births? I don’t know. If these declines have nothing to do with the pandemic, and they’re just the continuation of our trend toward lower birth rates, then that’s pretty shocking, too.

This is the total births by month and year, with 2018 and 2019 compared with 2020 so far:

Here are the monthly totals compared with the annual average decline in over the previous three years, which is 2.9% in California and 0.7% in Florida, which I call “predicted.”

In September 2020 versus September 2019, births were 6.1% lower in Florida and 9.6% lower in California. There is a lot of big news in the news these days, but I think this is still pretty big news. Again, if this has nothing to do with the pandemic that’s even more shocking.

Anyway, here’s the video:

5 minutes on the three-parent family

In the Atlantic article, “The Rise of the Three-Parent Family” I was quoted saying, “the increasing visibility and legalization of three-parent arrangements ‘is one of the signs that our definition of family is opening up.'”

That led to an interview with a different journalist. I recorded my end of the interview, and re-enact it here as a five-minute commentary. Could be suitable for a class discussion.

New COVID-19 and Health Disparities lecture

I recorded a new version of the lecture I created last spring: COVID-19 and Health Disparities. It defines health disparities, introduces the theory of fundamental causes, and then describes COVID-19 disparities by race/ethnicity and age with reference to education and occupational inequality. For intro sociology students.

Using data from Bureau of Labor Statistics (inspired by this piece from Justin Fox), I showed the percentage of workers working at home according to the median wage in their occupations, illustrating how people in lower-paid occupations aren’t working at home, while professionals and managers are:

And, using age- and race/ethnic-specific mortality rates from CDC, with population denominators from the 2018 ACS (I don’t know why I can’t find the denominators CDC uses), I made this:

The greatest race/ethnic disparities are in the working ages, which suggests they are driven at least partly by occupational inequality.

The lecture 23 minutes, slides with references and links are here.

Race and racism in America (video)

In my Social Problems class we’re spending the next few weeks on race, racial inequality, and racial politics. Step one is this lecture on race and racism.

After a tangent on racial identity, idealism and its enemies, I address biology and race, describing the classic racist racial categories in relation to vast human diversity in Africa and the world overall, with discussion of biological evolution and the sources of human variation. Then I turn to the US and discuss social definition and self-definition, race versus ethnicity, definitions of racism and discrimination, and how the Census Bureau measures US race and ethnicity, before summarizing current and projected race/ethnic composition. And I used the new Zoom feature where your PowerPoint slides are the virtual background (which is harder than it looks because your image isn’t mirrored while you speak!).

It’s 35 minutes. The slides are here, CC-BY: osf.io/uafvp. To see all my videos, visit my YouTube channel.

Measuring inequality, and what the Gini index does (video)

I produced a short video on measuring inequality, focusing on the construction of the Gini index, the trend in US family inequality, and an example of using it to measure world inequality. It’s 15 minutes, intended for intro-level sociology students.

I like teaching this not because so many of my students end up calculating and analyzing Gini indexes, but because it’s a readily interpretable example of the value of condensing a lot of numbers down to one useful one — which opens up the possibility of the kind of analysis we want to do (Going up? Going down? What about France? etc.). It also helps introduce the idea that social students of inequality are systematic and scientific, and fun for people who like math, too.

The video is below, or you can watch it (along with my other videos) on YouTube. The slides are available here, including one I left out of the video, briefly discussing Corrado Gini and his bad (fascist, eugenicist) politics. Comments welcome.

Pandemic Social Problems, with video and partial reading list

PN Cohen photo / CC-BY / https://flic.kr/p/2jw5juv

With a lecture and reading list, almost ready to start class.

Almost 6 months ago, on March 2, I had an informal COVID-19 debriefing with 50 students in my Social Problems class. Some of what I said came true, and I’m glad (sort of?) none of it was completely wrong (though we didn’t actually hit 100 million worldwide confirmed cases in May). For a reality check I go back to this Twitter thread, where I jotted down what I told them:

Now, as I prepare to teach the course online next week, I have updated my overview lecture, which has grown to 40 minutes.

Beyond some fundamentals, I’m tossing out the traditional Social Problems course outline and just doing the pandemic and related issues this semester, so this is the introductory lecture. I expect to record some more lectures. If I decide they’re not too embarrassing to share I’ll put them on my YouTube channel (which you can apparently subscribe to if you want to be notified of the videos). Feel free to use them for whatever you like, and pass along your feedback.

The course doesn’t start till next week, so I don’t have everything together yet, but I have a lot of readings, some for me and some for the students, which I’m sharing below.

Happy to have more suggestions, too.


The 1918 Flu pandemic

Race and Ethnic Disparities 

  • Hammonds, Evelynn M., and Susan M. Reverby. 2019. “Toward a Historically Informed Analysis of Racial Health Disparities Since 1619.” American Journal of Public Health 109 (10): 1348–49. https://doi.org/10.2105/AJPH.2019.305262.
  • Hogarth, Rana Asali. 2019. “The Myth of Innate Racial Differences Between White and Black People’s Bodies: Lessons From the 1793 Yellow Fever Epidemic in Philadelphia, Pennsylvania.” American Journal of Public Health 109 (10): 1339–41. https://doi.org/10.2105/AJPH.2019.305245.
  • Egede, Leonard E., and Rebekah J. Walker. 2020. “Structural Racism, Social Risk Factors, and Covid-19 — A Dangerous Convergence for Black Americans.” New England Journal of Medicine. https://doi.org/10.1056/NEJMp2023616.
  • Bobrow, Emily. 2020. “She Was Pregnant With Twins During Covid. Why Did Only One Survive?” New York Times, August 6, 2020, sec. New York. https://www.nytimes.com/2020/08/06/nyregion/childbirth-Covid-Black-mothers.html.
  • COVD race/ethnicity data: https://covidtracking.com/race/dashboard
  • Moore, Jazmyn T., Jessica N. Ricaldi, and Charles E. Rose. 2020. “Disparities in Incidence of COVID-19 Among Underrepresented Racial/Ethnic Groups in Counties Identified as Hotspots During June 5–18, 2020 — 22 States, February–June 2020.” Morbidity and Mortality Weekly Report 69. https://doi.org/10.15585/mmwr.mm6933e1.
  • Kim, Lindsay, Michael Whitaker, and Alissa O’Halloran. 2020. “Hospitalization Rates and Characteristics of Children Aged 18 Years Hospitalized with Laboratory-Confirmed COVID-19 — COVID-NET, 14 States, March 1–July 25, 2020.” Morbidity and Mortality Weekly Report 69. https://doi.org/10.15585/mmwr.mm6932e3.


Economic crisis and inequality

Gender and the lockdown

Government response

Anti-Asian racism

Trusting experts and confirmation bias, videos


Inequality, family change, and the pandemic (interview with Joanna Pepin)

Joanna Pepin was kind enough to interview me for her family sociology class (she’s just begun a new job at the University at Buffalo). We talked about why family sociology attracted me as an inequality researcher, what’s changed in modern families, some common misperceptions, what’s new the forthcoming edition of my textbook, and what COVID-19 is likely to mean for people and their families. In 11 minutes.

I hope it helps.