What’s the Biggest factor in Determining Who Votes in Local Elections? Age — Nothing Else Comes Close

Who Votes for Mayor?
4 min readOct 27, 2016

By Phil Keisling

The number one factor in predicting someone’s likeliness to vote is their age. Our “Who Votes for Mayor?” project showed that, in 50 cities across the country, older Americans cast ballots at dramatically higher rates than younger adults.

What’s more, age powerfully trumps all other key factors typically associated with lower turnout, including household income, educational attainment, and race/ethnicity. Even in heavily minority census tracts that contain their cities’ poorest, least educated voters, 65+ voters typically cast ballots at rates 2–5 times more often than 18–34 year olds in that same city’s most affluent and highly educated census tracts.

Younger city residents are often at the forefront of transforming the economic, demographic, and culture lives of their cities. But when it comes to policy-making and governance, our “Who Votes for Mayor?” study reveals they’re largely ceding those playing fields to their grandparents’ generation.

This trend of older folks dominating the ballot box is logically intuitive and well-documented. Far less clear until now is how dramatic the age gap really is between mayoral election voters and nonvoters — and how much that gap varies from city to city.

Since voter registration records almost always contain age or date of birth data, we can very accurately discern such things as the “Age Gap” between the median age of voting eligible residents, and those actually casting ballots.

In the nation’s 30 largest cities, this age gap averaged 15 years. While the median age of eligible voters was 42, the median for those casting ballots was 57 — almost a full generation older..

The age gap was less than a decade in only 4 cities: San Francisco and Seattle (9.2); Louisville (8.2) and Portland (4.0). Portland’s dramatic showing is attributable in part to being one of the few cities whose mayoral election coincided with the November 2012 presidential contest.

Meanwhile, the age gap was more than 20 years in four cities: Dallas (21); Miami (22.8), Las Vegas (23.0), and Fort Worth (25).

The median age of voters casting ballots was lowest in Portland (46); Seattle (50); Boston (51); and Columbus Ohio, Austin, and San Francisco (52). Las Vegas and Miami had the highest median age voter ages at 68.

Our study also determined a “Generational Clout Index” for each city. We calculated the odds of a 65+ resident being a voter rather than a non-voter, and then compared the result to the same calculation made for 18–34 year olds. If 75% of seniors voted and 25% didn’t — a 3:1 ratio — while just 33% of 18–34 year olds cast ballots (1:2), the Odds Ratio would be calculated as 6:1.

Among the 30 largest U.S. cities, the median Generational Clout Index of 65+ city residents relative to their 18–34 year old counterparts was 7:1. This “Generational Clout Index” was highest in Ft. Worth (43:1) and Las Vegas (30:1) — and lowest in Portland (2:1); and Seattle, Boston, and Louisville (3:1).

By geocoding more than 22 million voting records and then layering census data on city maps, the “Who Votes for Mayor?” study also allows journalists, researchers, and citizens to analyze each city’s age-related trends down to the Census Tract level.

Demographic data such as race, median income and education aren’t typically known at the individual voter level, so caution must be exercised whenever analyzing correlations between them and voting patterns. But virtually everywhere, we can see that age plays a powerful role in electoral outcomes.

Take Chicago, one of the nation’s most diverse cities when it comes to income and ethnicity.. Chicago’s overall turnout was a relatively high 33% in its 2nd round 2015 mayoral run-off election where incumbent Mayor Rahm Emanuel survived a spirited challenge from Jesus Garcia.

Chicago’s Lincoln Park neighborhood contains some of the highest median household incomes, nearly triple the citywide average. Education, homeownership, and non-minority population are also some of the city’s highest. Yet in three selected and adjacent Lincoln Park census tracts, turnout among 18–34 year olds ranged from 5 to 20%.

Contrast this with three selected and adjacent census tracts from South Chicago’s Woodlawn neighborhood, There, median household income is roughly one-third of the citywide average, and residents are predominately minority. In these tracts, 65+ residents cast ballots at rates between 51–67% of the voting age population.

In every major city, the same examples abound — many of them even more dramatic, especially when overall city turnout runs far lower than Chicago’s.

Actual voter turnout among younger residents is now so low, in vast swaths of most American cities, that mayoral candidates arguably would be acting against their own political self interest in searching out — much less actively courting — such voters. So is it any wonder that many key issues don’t receive the attention they might otherwise deserve –or only gain traction once a full-fledged crisis is underway?

Next up: Race Matters, too — but in some surprising ways.

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Who Votes for Mayor?

A project of Portland State University examining the electoral dynamics of mayoral elections in the 50 largest U.S. cities.