The Lindahl Letter
The Lindahl Letter
Bayesian Models and Elections (150th post)

Bayesian Models and Elections (150th post)

Maybe a longer title for this post could be, “Bayesian Models and Elections: A Dive into the Dance of Uncertainty.” This is the 150th transmission of the Lindahl Letter.

In the vast and often unpredictable theater of electoral forecasting, the quest for precision is a relentless pursuit. The choreography of voter behavior is a complex ballet, orchestrated by a myriad of factors—societal tremors, economic tides, the charisma of candidates, and the machinations of campaign strategies. Amidst this swirling cauldron of variables, the call for a more nuanced forecasting method is loud and clear. And what answers the call with a finesse born of probabilistic reasoning is the realm of Bayesian models. These statistical marvels stand at the confluence of data and uncertainty, offering a refined lens to dissect the electoral enigma.

The essence of Bayesian statistics, a legacy of Thomas Bayes, is a narrative of evolving beliefs in the face of emerging evidence. It's a realm where estimates aren't static, but dynamic, continually reshaped by the rhythm of new data—a narrative that resonates with the pulsating heart of electoral dynamics.

In the Bayesian narrative, the tale begins with initial beliefs, our prior probabilities. As the story unfolds with new data—the likelihood—our beliefs morph, culminating in updated beliefs or posterior probabilities. This dance of iterative learning is akin to the dynamism of electoral scenarios, where a single debate, policy announcement, or campaign rally could tilt the scales of public sentiment.

A compelling act in the Bayesian play is its ability to weave historical election data into the forecasting fabric. It’s not just about the now, but a dialogue with the past, understanding how the ghost of incumbency, the whisper of economic indicators, or the shout of demographic shifts have choreographed electoral outcomes before.

And then, there’s the magnum opus of Bayesian models—the articulation of uncertainty. Unlike the static snapshot often rendered by traditional polling, Bayesian models compose a symphony of probability distributions. They unveil a spectrum of possible electoral outcomes, each with its associated probability, painting a picture of electoral reality that's as rich as it is realistic.

The spotlight often falls on case studies like the 2012 and 2016 U.S. Presidential Elections, where the Bayesian choreography, as orchestrated by platforms like Nate Silver’s FiveThirtyEight, navigated the electoral tumult with a commendable degree of accuracy. By embracing uncertainties and dancing with historical context, Bayesian models orchestrate a forecast that traditional polling methods seldom match.

Yet, the narrative isn’t without its share of cliffhangers. The hurdles of data scarcity, model misspecification, and computational intricacies are challenges that beckon solutions. Despite these, the Bayesian voyage into electoral forecasting holds a promise—of rendering narratives that are not only statistically sound but resonate with intuitive clarity.

As the electoral saga continues to unfold, the allure for better forecasting tools is a relentless whisper. Bayesian models, with their eloquence in narrating the dance of uncertainty, emerge as potent companions for pollsters and policymakers. They underline an electoral truism—in a realm replete with uncertainties, understanding and embracing these uncertainties isn’t just the hallmark of wisdom, but a cornerstone of robust electoral forecasting.

A few scholarly articles I found interesting this week:

Linzer, D. A. (2013). Dynamic Bayesian forecasting of presidential elections in the states. Journal of the American Statistical Association, 108(501), 124-134. 

Lock, K., & Gelman, A. (2010). Bayesian combination of state polls and election forecasts. Political Analysis, 18(3), 337-348. 

Heidemanns, M., Gelman, A., & Morris, G. E. (2020). An updated dynamic Bayesian forecasting model for the US presidential election. Harvard Data Science Review, 2(4), 10-1162. 

Olsson, H., Bruine de Bruin, W., Galesic, M., & Prelec, D. (2021). Election polling is not dead: a Bayesian bootstrap method yields accurate forecasts. Preprint at 

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The Lindahl Letter
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