Data-driving over 2.3 million voters to the polls

Mica Alaniz
DNC Tech Team
Published in
6 min readNov 27, 2018


In the run-up to the 2018 midterm elections, the DNC’s polling location data helped more than two million voters locate their polling place. We supported 20 embeddable IWillVote (IWV) Polling Place Locator widgets in English and Spanish across 12 states, including some of the biggest campaigns, such as Beto for Texas and Kyrsten Sinema for Arizona. That same polling location data also served as the backbone for all our voter protection work.

The DNC’s goal is to help Democrats win from the school board to the White House. Within that, the DNC’s Tech team’s mandate is to make data accessible to help drive and inform election staff and volunteers in all those races. Each year the DNC takes on a massive project in support of that goal: provide a list of places each American can vote and use it to power nationwide programs working in the public interest.

It should go without saying, but this work is measured in votes delivered. We want to ensure voting is easy and convenient for everyone, so reducing the friction to casting a ballot is one of the most important pieces of our work. If a voter shows up at the wrong location, or if a location is closed, then that voter may not actually vote. A single mistake could mean lost votes and a less representative democracy.

This is all surprisingly complex. On Election Day 2018, there were nearly 90,000 locations across the country to cast your ballot. Voters could vote at an Election Day polling place, drop off mail-in ballots at a dropbox, or head to their county’s vote center. It’s daunting to think about the challenge of collecting information on every location, as well as associated data such as hours and dates open. In addition, and unsurprisingly, it’s hard to work with: the data isn’t standardized, it has to be precisely geocoded, and it could potentially change up until the last moment as locations move or polls stay open longer on Election Day.

Acquiring polling place data

The start of everything is data acquisition and the work put in to maintain the data’s accuracy and integrity. While many think of Election Day as a one-day-a-year phenomenon, the reality is that it’s a marathon and not a sprint. The DNC Tech team partnered with state Democratic parties to acquire nearly all 90,000 polling places nationwide both on and before Election Day.

Early Voting begins as soon as mid-September in some states. And from that day onward, polling locations set up, open their doors, and then close down nearly daily all over the country. For example, Texas’ Travis County enjoys “mobile early voting locations” which literally change locations every day. Some other locations open for only a few days at a time, with limited hours.

Our lines of communication with people on the ground are so crucial. While some state parties receive a list of polling locations from their state election official months in advance, others must make calls to each individual county in order to acquire data. This can be an arduous, lengthy process, involving multiple updates. Once there is a preliminary “source of truth” for where and when voters can cast their ballot, there is a shift towards last minute updates. When you see a breaking news story about a polling station that has lost power or caught fire, there is a scramble on the backend to update this information and ensure voters are aware of the change.

Each update the DNC Tech team receives from the state party kicks off a process of normalizing and geocoding the new data and updating our polling location data to reflect the new information. All these notifications of polling place closures and changes occur in real time, and our Polling Place Locator and its data are updated within minutes of any change.

I Will Vote and the Polling Place Locator

The Polling Place Locator not only helped over two million voters successfully locate their polling place, but also endured tsunamis of traffic after tweets and other social media posts throughout the cycle (Thanks, Obama!).

An Obama bump live in action

For those curious about our technology choices, after processing the data from states, we load it into a Postgres (our relational database of choice) RDS instance. From there, we surface the data through a Flask-based JSON API, which is consumed by the Polling Place Locator (a React app). The API-first approach has allowed us to write other applications that consume the data as well as open our data to partner organizations.

Of course, our data model needs to reflect reality. The ways that people can cast a ballot is ever changing and ever evolving. For example, Arizona now has a dual vote center and traditional polling places method of voting for Election Day. Our model supports all the ways that you can cast your ballot:

  • Early Voting Locations, as in Louisiana
  • Ballot Drop Boxes, like in Oregon or Washington state
  • Traditional Election Day Locations
  • Election Day Vote Centers, like in Arizona
  • Hybrid Voting Systems

Polling Place widgets

We also firmly believe that all politics are local, and we wanted the ability for campaigns to be able to directly benefit from all our work in their own communications. Again, our goal was to make casting a ballot, and therefore finding the polling location, as frictionless as possible. If a voter visited their favorite candidate’s website, they should see their polling place listed.

To handle this use case, the DNC created an embeddable “widget” for IWV’s Polling Place Locator to allow campaigns and state parties to allow their website’s visitors to look up where to vote and customize each widget to their brand.

These widgets were used extensively in Texas and Illinois, in both English and Spanish language versions. Over 300k voters were able to look up their polling place through the 20 embedded IWV widgets on campaign and state party websites.

Voter Protection

Not only did we serve voters directly, but the DNC Tech team also provided polling location data to voter protection programs both at the DNC and across the country. It’s important to get a voter to the right polling place, but, we also need to make sure a voter’s rights are defended once they get there.

The DNC’s Voter Protection Hotline alone answered over 7,000 calls leading up to and on Election Day, many of which were polling place lookup questions from those who were unable to access the information themselves. Polling location data is a crucial linchpin for a voter protection application that synchronized the DNC’s HQ operations with on-the-ground poll observers and volunteers.

More states than ever used our data to track and record voting incidents as well as questions from voters. Nearly 15,000 volunteers across 41 states answered Voter Protection Hotline calls, observed voting sites, and provided information about where and how to vote. Our polling location data helped states place those volunteer poll observers at crucial precincts and make sure that they could accurately mark where and when problems at polling places occurred.


We’re excited to continue this work as we believe that it is crucial to protecting the right to vote nationwide. We’re look forward to supporting further special elections like today’s U.S. Senate runoff election in Mississippi, the forthcoming runoff elections in Louisiana on December 8 and in Georgia on December 4.

Thanks to the contributions of people from the DNC’s Tech, Voter Protection and Mobilization teams: Colin Fleming, CM Lubinski, Kat Atwater, Andrea MacVay, Ariana Hooks, Tessa Simonds, Jose Nunez, Lennon Day-Reynolds, Akiva Leffert, Andrew Callahan, Viola Glenn, and Catherine Tarsney.



Mica Alaniz
DNC Tech Team

And if it wasn’t for the music, I don’t know what I’d do. Chicago Always, but Coffee First. I work in tech and politics. She/Her.