Voter Turnout in Massachusetts
How Did Demographics Affect Voter Turnout in the 2020 Presidential Election?
Understanding Voter Turnout
- Why Voter Turnout Matters - Voter turnout reflects public engagement in democracy. High turnout ensures broader representation. Low turnout highlights barriers to participation.
- Demographics and Turnout - Research shows that turnout varies by demographics like age, income, and ethnicity. Identifying these patterns helps address gaps in representation.
- About This Site - You can explore voter turnout in Massachusetts for the 2020 election. You can make guesses, compare them to our model, and uncover key demographic insights.
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CS 1710 - Official Ballot 2024
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| INSTRUCTIONS | TEAM MEMBERS | VOTE FOR ONE |
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Max Bahar
Harvard University
MS Data Science 2026
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Ted McCulloch
Harvard University
MS Data Science 2026
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Stefan Chu
Harvard University
MS Data Science 2026
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Anitej Thamma
Harvard University
MS Data Science 2026
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| QUESTION | CATEGORIES | SELECT UP TO THREE |
| Which demographic categories do you think have the greatest impact on voter turnout, positively or negatively? |
Party Affiliation
Democrat, Republican, etc.
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Average Income
High, Middle, Low
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Gender
Male, Female, Unknown
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Spoken Language
English, Spanish, Italian, etc.
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Age
Younger, Older, etc.
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Ethnicity
European, Hispanic, Asian, etc.
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Reviewing Your Selections
You have made no selections, please return to previous slide to vote.
What do you think the voter turnout was in for the 2020 Presidential Election?
The average 2020 presidential voter turnout in Massachusetts is
Click and drag the slider above to make your guess.
Exploring Voter Trends
Voter turnout and demographics vary across Massachusetts.
On the map to the right, you can explore key information such as voter turnout, the number of registered voters, and average household income across the state.
Click on any area to dive deeper into its demographics. You can view detailed distributions of voter age, gender, party affiliation, ethnicity, or language.
Areas with Low Voter Turnout
Focusing on areas and demographic characteristics associated with low voter turnout may help government officials focus their efforts.
These characteristics are associated with lower voter turnout:
- Lower mean household income.
- Higher percentage of people that identify as hispanic.
Map of Voter Turnout in Massachusetts
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by Geography: |
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by Category: |
Voter Turnout Kernel Density Estimate
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by Category: |
Legend
Turnout Trends Across Demographics
Kernel density plots allow you to visualize the density of data observations
X-axis - of the registered, voting population (of a block group), this proportion belonged to the category
Y-axis - voter turnout for a block group
Example Interpretation - The density of females is to the right of males as there tend to be more women registered to vote than men.
Dashed lines are to aid with plot readability
Voter Turnout Across Counties
We find that Hampden county has the lowest voter turnout, with 10% lower voter turnout compared to other counties.
On the other hand, Barnstable and Hampshire county are tied for the highest voter turnout, with 4% higher voter turnout compared to other counties.
Party Affiliation in Massachusetts
The diverging bar plot visualizes how voter turnout in Massachusetts counties deviates from the average 81% voter turnout.
Use the dropdowns to see the proportion of each party's voters in each county.
The bars are shaded dynamically, with lighter or darker hues indicating the proportion of the dominant party in each county.
Voter Turnout by County by Party
How Do We Uncover the Demographic Drivers of Voter Turnout?
Leveraging data and models to understand voter behavior in Massachusetts.
Random Forest Model
A Decision Tree predicts outcomes by splitting data into branches based on yes/no questions. While useful, single trees can overfit and perform poorly on unseen data.
Our team uses a Random Forest, which improves accuracy by combining decisions from multiple trees, capturing complex patterns and reducing overfitting.
Key Inputs
We identified the most important predictors by measuring feature importance. These include:
- Proportion of voters aged 20-24, 25-29, 30-34, and 45-55.
- Proportion of voters with European, African American, Hispanic, and "Other" ethnicities.
- Proportion of female voters.
- Mean household income.
- Total number of registered voters.
Predictive Output
The Random Forest model predicts voter turnout in the 2020 presidential election for each Census Block Group in Massachusetts, based on demographic data. Key findings include:
- Higher turnout is linked to higher income and more registered Democrats.
- Lower turnout is linked to higher proportions of Hispanic voters and non-English speakers.
Impact on Voter Turnout
The plot to the right shows SHAP values, measuring the impact each feature has on the model's predictions.
Features at the top are most influential, while those at the bottom are less impactful.
Key Demographics Driving Turnout
Mean household income, unknown language, and Hispanic ethnicity are the most impactful features on average.
High variable values are shown in red, while low values are shown in blue.
For example, high household income slightly increases turnout predictions, while low income decreases them significantly.
Similarly, block groups with high proportions of voters in the unknown language category (that are likely non-English speakers) or Hispanic ethnicity tend to lower turnout predictions.
SHAP Model Feature Importance
Model Prediction Results
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by Geography: |
Comparing Predictions and Reality
You predicted that had a voter turnout of .
Our model predicted that the county had a voter turnout of .
In reality, the county had a voter turnout of .
Insights from Model Results
Click on any area to see how each demographic feature affected the turnout prediction for that area.
The tooltip shows how much each feature influences the model's local prediction for that area.
The prediction always starts at a base SHAP prediction of 78.74%. Then each feature is shown positively influencing the voter turnout prediction in red or negatively in blue.
Predictions closely align with actual turnout, validating the use of demographic data for understanding voter engagement.
If voting is not equitable,
what can be done?
Making Voting More Accessible
- Voter Registration Reform - Universal automatic registration, same day registration, and online registration
- Expanding Voting Access - Increasing access to mail-in/absentee ballots and extended voting/early voting hours
- Reducing Polling Place Closures - Minority-heavy areas are particularly susceptible to having polling places closed or moved, making voting more difficult
Addressing Corruption
- Campaign Finance Reform - Ensuring that elections are not disproportionately influenced by wealthier individuals or corporations
- End Gerrymandering - Independent, non-partisan commissions can ensure fairer, more representative district boundaries
- Limit Purging of Voter Rolls - Many states engage in "voter roll purging," which can incorrectly remove eligible voters from the rolls
Education and Outreach
- Civic Education Programs - Increasing the focus on civic education in schools and communities can improve voter literacy and confidence
- Community-Based Voter Outreach - Engaging in targeted outreach to underrepresented groups through grassroots organizations can help improve voter turnout in marginalized communities. This can include providing information in different languages, assisting people with understanding their voting rights, and offering transportation to polling stations.
Thanks for listening!
Max BaharHarvard UniversityMS Data Science 2026 |
Stefan ChuHarvard UniversityMS Data Science 2026 |
Ted McCullochHarvard UniversityMS Data Science 2026 |
Anitej ThammaHarvard UniversityMS Data Science 2026 |