Ceteris Paribus: Red States, Blue States, Longevity, and Health
Settling a dispute between Dr. Duarte and Dr. Knowles on red state/blue state policies and their impact lifespans.
[Note - Dr. Knowles originally agreed to review this before I published it, and as of 3-8-25 my last couple of attempts to reach out to him were unsuccessful. So the new plan is to publish now and edit this if/when he gets back to me.]
Dr. Duarte is a Twitter friend of mine and a fellow academic pirate, and he recently made some pretty strong claims about a paper published in Nature Medicine written by Jay Van Bavel, Shana Kushner Gadarian, Eric Knowles & Kai Ruggeri titled ‘Political Polarization and Health.’ Their article claimed that blue state’s liberal policies explained higher life expectancies.
While Dr. Duarte and I were discussing it on X, Dr. Knowles joined the conversation and said that Dr. Duarte was wrong about the studies they had used to reach their conclusion. I promised them both that I’d do my homework instead of just trusting a member of my academic ingroup, and here’s how my investigation went.
Summary
Van Bavel et al. (2024) asserted in Nature Medicine that political polarization, via state policy differences, shapes U.S. life expectancy, with liberal states outperforming conservative ones. Their claim that people in states with more liberal social policies live longer cites Montez (2020) and highlights COVID-19 disparities (Wallace et al., 2023). Duarte challenged this as methodologically flawed and ideologically skewed (Duarte, 2025), while co-author Dr. Eric Knowles defends its grounding in Montez et al. (2020). The core issue is Ceteris Paribus (all other things being equal), and whether Van Bavel et al. (2024) chose the correct variables to compare populations.
I reviewed their arguments and have added a list of possible exogenous factors that should be considered in future research.
The Dispute
Van Bavel et al. (2024) link polarization to health, citing a 43% higher excess death rate among Republicans during COVID-19 (Wallace et al., 2023) and Montez (2020)’s New York-Mississippi comparison (80.6 vs. 74.4 years). Duarte (2025) deemed Montez (2020) a non-empirical essay, unfit for causal inference, and critiques its omission of race. Mississippi’s population is 38% Black population while New York’s is 15% (Andrasfay & Goldman, 2022). The paper they cite also has a liberal bias. Knowles (2024) countered that Montez (2020) synthesized Montez et al. (2020), which models a 2.8-year life expectancy gain for women under liberal policies, bolstered by COVID-19 evidence (Gollwitzer et al., 2020).
Duarte’s Critique
Duarte’s assessment of Montez (2020) as analytically weak is generally accurate, if not a bit blunt, as its descriptive table lacks statistical rigor (Montez, 2020), falling short of causal standards (Ioannidis, 2005). Race omission is a critical flaw as there is a significant Black-White life gap in life expectancy (73.2 vs. 77.3 in 2021, Andrasfay & Goldman, 2022). This racial gap suggests demographic composition drives disparities, which was not addressed by Montez et al. (2020)’s immigration-only controls (Borrell et al., 2006).
Duarte’s charge of bias that Van Bavel et al. (2024) favor liberal policies is reasonable as it doesn’t include counterexamples like school closure harms (Betthäuser et al., 2023), and thus fails to have a balanced approach (Tetlock, 1994).
However, his dismissal of Montez et al. (2020) as “invalid” overreaches, given its 50-state scope, but highlights causal overstatement (Hill, 1965).
Knowles’ Defense
Knowles (2024) defends Montez et al. (2020)’s 45-year, 135-policy analysis, estimating gun control adds 0.5 years for women, supported by firearm mortality reductions for both sexes (Fleegler et al., 2013). COVID-19 data—14% less distancing in red counties (Gollwitzer et al., 2020) reinforces polarization’s toll.
Yet, Montez et al. (2020) admits associative limits, and Van Bavel et al.’s (2024) “impact” phrasing exceeds this (Hill, 1965). Knowles’ silence on race weakens his rebuttal, despite the paper’s breadth (Harper et al., 2007).
Conclusion
Duarte’s critique of methodological gaps regarding race and rigor is correct, upheld by Montez (2020)’s thin evidence and Montez et al. (2020)’s confounder oversight. Knowles’ data scope is robust, but causal claims falter without addressing Duarte’s points fully.
Better Models for Partisan Longevity Research
Beyond policy, exogenous factors may drive disparities:
1. Socioeconomic Inequality: Red states’ higher poverty (e.g., Mississippi 19.6% vs. New York 13.9%) links to worse health (Pickett & Wilkinson, 2015), compounded by economic shocks (Case & Deaton, 2020).
2. Cultural Norms: Red-state individualism resists health measures (Gollwitzer et al., 2020), with tobacco norms entrenched historically (Brandt, 2007).
3. Environmental Hazards: Red states’ industrial bases (e.g., coal in West Virginia) increase exposure risks, beyond policy control (Montez et al., 2020).
4. Healthcare Access: Rural red states face provider shortages (e.g., Mississippi 12.3 vs. New York 22.1 docs/100,000), a market-driven gap (Rural Health Information Hub, 2022).
5. Demographic Shifts: Red states’ older, minority-heavy populations (e.g., Mississippi 38% Black) and blue-state migration of young professionals skew outcomes (Andrasfay & Goldman, 2022).
Exogenous factors such as poverty, culture, environment, access, and demographics offer a fuller lens on red-blue health and longevity gaps. Adding them, and including race, would vastly improve Van Bavel et al. (2024)'s work and create the necessary conditions for ceteris paribus and produce robust enough models (Diez Roux, 2001) to compare the populations of red and blue states.
References
Andrasfay, T., & Goldman, N. (2022). Reductions in US life expectancy during the COVID-19 pandemic by race and ethnicity: Is 2021 a repetition of 2020? PLOS ONE, 17(8), e0272973. https://doi.org/10.1371/journal.pone.0272973
Betthäuser, B. A., Bach-Mortensen, A. M., & Engzell, P. (2023). A systematic review and meta-analysis of the evidence on learning during the COVID-19 pandemic. Nature Human Behaviour, 7(3), 375–385. https://doi.org/10.1038/s41562-022-01506-4
Borrell, L. N., Kiefe, C. I., Williams, D. R., Diez-Roux, A. V., & Gordon-Larsen, P. (2006). Self-reported health, perceived racial discrimination, and skin color in African Americans in the CARDIA study. Social Science & Medicine, 63(6), 1415–1427. https://doi.org/10.1016/j.socscimed.2006.04.008
Brandt, A. M. (2007). The cigarette century: The rise, fall, and deadly persistence of the product that defined America. Basic Books.
Case, A., & Deaton, A. (2020). Deaths of despair and the future of capitalism. Princeton University Press.
Diez Roux, A. V. (2001). Investigating neighborhood and area effects on health. American Journal of Public Health, 91(11), 1783–1789. https://doi.org/10.2105/AJPH.91.11.1783
Duarte, J. (2025, February 14). NYU social psychologists make false claims about gun control and life expectancy. Valid Science by José Duarte, PhD. Substack.
Fleegler, E. W., Lee, L. K., Monuteaux, M. C., Hemenway, D., & Mannix, R. (2013). Firearm legislation and firearm-related fatalities in the United States. JAMA Internal Medicine, 173(9), 732–740. https://doi.org/10.1001/jamainternmed.2013.1286
Gollwitzer, A., Martel, C., Brady, W. J., Pärnamets, P., Freedman, I., Knowles, E. D., & Van Bavel, J. J. (2020). Partisan differences in physical distancing are linked to health outcomes during the COVID-19 pandemic. Nature Human Behaviour, 4(11), 1186–1197. https://doi.org/10.1038/s41562-020-00977-7
Harper, S., Lynch, J., Burris, S., & Davey Smith, G. (2007). Trends in the black-white life expectancy gap in the United States, 1983-2003. JAMA, 297(11), 1224–1232. https://doi.org/10.1001/jama.297.11.1224
Hill, A. B. (1965). The environment and disease: Association or causation? Proceedings of the Royal Society of Medicine, 58(5), 295–300. https://doi.org/10.1177/003591576505800503
Ioannidis, J. P. A. (2005). Why most published research findings are false. PLoS Medicine, 2(8), e124. https://doi.org/10.1371/journal.pmed.0020124
Knowles, E. (2024, October 28). [X thread starting with post ID 1888434805974475190]. https://x.com/eric_knowles/status/1888434805974475190
Jennifer Karas Montez, How State Preemption Laws Prevent Cities from Taking Steps To Improve Health and Life Expectancy, Scholars (Mar. 6, 2018). Link to PDF can be found here. (mentioned in the Twitter exchange)
Montez, J. K. (2020). Policy polarization and death in the United States. Temple law review, 92(4), 889. https://pmc.ncbi.nlm.nih.gov/articles/PMC8442849/
Montez, J. K., Beckfield, J., Cooney, J. K., Grumbach, J. M., Hayward, M. D., Koytak, H. Z., Woolf, S. H., & Zajacova, A. (2020). US state policies, politics, and life expectancy. The Milbank Quarterly, 98(3), 668–699. https://doi.org/10.1111/1468-0009.12469
Pickett, K. E., & Wilkinson, R. G. (2015). Income inequality and health: A causal review. Social Science & Medicine, 128, 316–326. https://doi.org/10.1016/j.socscimed.2014.12.031
Rural Health Information Hub. (2022). Healthcare access in rural communities. https://www.ruralhealthinfo.org/topics/healthcare-access
Tetlock, P. E. (1994). Political psychology or politicized psychology: Is the road to scientific hell paved with good moral intentions? Political Psychology, 15(3), 509–529. https://doi.org/10.2307/3791569
Van Bavel, J. J., Gadarian, S. K., Knowles, E., & Ruggeri, K. (2024). Political polarization and health. Nature Medicine, 30(11), 3085–3093. https://doi.org/10.1038/s41591-024-03307-w
Wallace, J., Goldsmith-Pinkham, P., & Schwartz, J. L. (2023). Excess death rates for Republican and Democratic registered voters in Florida and Ohio during the COVID-19 pandemic. JAMA Internal Medicine, 183(9), 916–923. https://doi.org/10.1001/jamainternmed.2023.1154