On October 3 2022, journalist James Surowiecki tweeted about a “new study” of post-vaccine pandemic mortality, contrasting deaths in Florida and Ohio with voter registrations:
In the tweet, Surowiecki described an analysis of “almost 600,000 deaths” in the two states. He indicated that registered Republicans had “far higher” rates of excess death, and that the gap was observed after the introduction of vaccines around December 2020.
It is not uncommon for social media posts about research or “a new study” not to contain links or citations. However, Surowiecki also posted a link to NBER.org, the website for the non-partisan National Bureau of Economic Research.
That link led to a PDF copy of a paper with the title, “Excess Death Rates for Republicans and Democrats During the Covid-19 Pandemic,” with a note at the top marking it as a “working paper.” Research in pre-print or working papers frequently circulated in early 2020, and as we explained of the designator:
At the very start of the piece, [an outlet] identified [their] source material as a “working paper,” i.e. typically not yet peer-reviewed.
Although some working papers were leveraged to spread highly corrosive disinformation early on in the pandemic, preprints also helped to bridge knowledge gaps in introducing research findings to the public at critical times. Moreover, NBER typically maintains a level-headed and data-heavy view of the information it processes.
An abstract for the NBER working paper provided context about the purpose of the research and described the researchers’ methodology:
Political affiliation has emerged as a potential risk factor for COVID-19, amid evidence that Republican-leaning counties have had higher COVID-19 death rates than Democrat- leaning counties and evidence of a link between political party affiliation and vaccination views. This study constructs an individual-level dataset with political affiliation and excess death rates during the COVID-19 pandemic via a linkage of 2017 voter registration in Ohio and Florida to mortality data from 2018 to 2021.
It continued with a hypothesis that registered Republicans were likelier to be counted among excess deaths than registered Democrats. The authors mentioned a detail from in the tweet about mortality after vaccines were made publicly available in late 2020 and early 2021 — in other words, after the point that ideology and information (or lack thereof) could disrupt survival:
We estimate substantially higher excess death rates for registered Republicans when compared to registered Democrats, with almost all of the difference concentrated in the period after vaccines were widely available in our study states. Overall, the excess death rate for Republicans was 5.4 percentage points (pp), or 76%, higher than the excess death rate for Democrats. Post- vaccines, the excess death rate gap between Republicans and Democrats widened from 1.6 pp (22% of the Democrat excess death rate) to 10.4 pp (153% of the Democrat excess death rate). The gap in excess death rates between Republicans and Democrats is concentrated in counties with low vaccination rates and only materializes after vaccines became widely available.
Following the abstract, the authors cited earlier research which “established differences in vaccination attitudes and social distancing based on political party affiliation,” adding that “it has been more difficult thus far to establish corresponding links to health outcomes due to data limitations.” Researchers approached that challenge by “linking voter registration data in Ohio and Florida to mortality data to assess the individual level association,” adding:
We estimate higher excess death rates for registered Republicans when compared to registered Democrats after vaccines were widely available — and not before — and these differences were concentrated in counties with lower vaccination rates.
A “Results” section described the total number of deaths, and the voting records used to inform calculations:
To calculate excess deaths, we use 577,659 deaths of individuals linked to their 2017 voting records in Ohio and Florida who died at age 25 or older between January 2018 and December 2021. Our approach estimates “excess death rates” as the percent increase in deaths above expected deaths that are due to seasonality, geographic location, party affiliation, and age.
Under “Discussion,” the authors reiterated:
Political party affiliation was associated with excess death rates at the individual level during the initial years of the COVID-19 pandemic. Registered Republicans in Florida and Ohio had higher excess death rates than registered Democrats, driven by a large mortality gap in the period after all adults were eligible for vaccines. These results adjust for county-by-age differences in excess deaths during the pandemic, suggesting that there were within-age by-county differences in excess death associated with political party affiliation.
This information also bolsters the results of previous studies, including one published in June 2022 that showed that the mortality gap simply exacerbated what was already a decades-long pattern:
In a study published in June in The BMJ, Warraich and his colleagues showed that over the two decades prior to the pandemic, there was a growing gap in mortality rates for residents of Republican and Democratic counties across the U.S. In 2001, the study’s starting point, the risk of death among red and blue counties (as defined by the results of presidential elections) was similar. Overall, the U.S. mortality rate has decreased in the nearly two decades since then (albeit not as much as in most other high-income countries). But the improvement for those living in Republican counties by 2019 was half that of those in Democratic counties—11 percent lower versus 22 percent lower.
On October 3 2022, the Washington Post published an analysis of the working paper with the headline, “After vaccines became available, a partisan gap in deaths emerged.” It referenced ongoing speculation about mortality rates along party lines, and how the NBER research quantified that gap:
Why might it be the case that places with more Trump voters saw more deaths?
Well, we know that many of those who died of the virus last year  were unvaccinated. The Kaiser Family Foundation estimates that some 234,000 deaths from June 2021 through March  could have been prevented had the decedents been vaccinated against the virus. That protection, too, held into the omicron era.
We also know that Republicans were less likely to get vaccinated than Democrats. Republican officials often downplayed the utility of vaccination, responding to framing of the shots as an unnecessary intrusion from the government. Trump-voting counties were also more likely to seek alternative treatments for covid like the drug ivermectin — treatments that were shown repeatedly not to be effective.
All of this, though, was correlation. We couldn’t say that more Republicans were dying, specifically, so the link to partisanship was indirect, however clearly rational an assumption it might have been.
[In September 2022], though, the National Bureau of Economic Research published an important study from researchers affiliated with Yale University….
A popular October 3 2022 tweet claimed that a new study of more than half a million deaths in Ohio and Florida shows that “registered Republicans had far higher excess-death rates than registered Democrats during the pandemic, with almost all of that gap coming after vaccines were available.” NBER published a working paper in September 2022, cross-referencing excess deaths with voting data in Ohio and Florida. Researchers found that after the introduction of vaccines, a pattern emerged in those states, with registered Republican voters dying at rates in excess of registered Democrats. In the context of the research, the availability of vaccines created an unintentional divergence point between registered voters of different parties.