Reaching the right voters in a Democratic primary

April 19, 2021
Targeting in primaries is tough! Turnout is usually pretty low and it can be hard to differentiate your supporters from your opponents' supporters. So who should you try to mobilize? Who should you try to persuade? Should you even have a turnout or persuasion program at all?

At the highest level, there are two ways to increase your vote share in an election: 1) increasing participation among people who are likely to support you, and 2) gaining the support of people who are likely to vote but not already likely to support you.

Increasing turnout among your supporters

Over the past decade, turnout in primaries has been about 30% as large as general election turnout. In theory, this creates a huge opportunity. Even if you had just 35% baseline support in a two-way race, you could win a majority of votes just by getting all of your likely supporters who vote in general elections but not primary elections to vote in the primary.

However, this approach would require a pretty confident idea of who your likely supporters are. Without that knowledge, increasing turnout could actually hurt your chances by making your persuasion burden greater. You don’t want that!

How to identify your supporters in a primary

This is where Deck steps in. Our predictions consider what makes each campaign (and each district) unique. This includes the traits of your (and your opponents’) contributors, endorsements you may have received, your history (if any) in elected office, and how your contest is being covered in local media.

With this data, we’re able to generate support scores for specific campaigns in a primary that usually work just as well as general election support scores.

We also have generic primary support scores we’ve trained based on candidates’ ideological leanings, showing the probability a person would vote for a generic progressive challenger (such as AOC, Ilhan Omar, Bernie Sanders, or Jamaal Bowman) over a moderate incumbent.

How to identify your likely supporters without Deck

We believe we’ve built some pretty powerful (and affordable!) tools for doing better targeting in a primary. But if you’re not using Deck, there are still some simple ways you can adapt our methods in your race.

Review previous precinct-level election results.

If you identify as a progressive, you might look at where Bernie Sanders or Elizabeth Warren did the best in the 2020 presidential primary. Or if you think you have a lot in common with previous statewide or congressional primary candidates, you might look for where they succeeded as well. You can find these precinct-level results through your state or county election administrator. Other good public sources for precinct-level election results include and the MIT Election Lab.

Look up contributors to national candidates you’re aligned with.

According to Pew, 1 in 4 registered voters made a campaign contribution in 2020. And thanks to state contribution systems, it’s pretty easy to look up itemized contributions to state and local campaigns you might identify with.

While it’s usually illegal to use past contributions records to solicit new contributions, this is still a good way to understand the profile of the voters you might want to focus your outreach on. Even just reviewing the distribution of past contributions by ZIP code might lead to some surprising insights!

Note: Contributors are not a representative sample of voters! They’re usually higher income and more deeply engaged in politics, for example. But you can still learn a lot by analyzing this data.

Use the supporter data you’ve collected yourself!

While field IDs collected through voter contact often reflect more support than you might actually have, they’re still a great way to understand what traits are differentiating your supporters, your opponent’s supporters, and people who don’t yet know whom to support.

Your Facebook page is another rich resource. For example, you might use Facebook Ads to create a lookalike audience based on your page’s followers (or followers of aligned candidates’ pages) — and limited to your district’s geography! — to run turnout-focused digital ads.

Increasing support among likely voters

Given the difficulty of identifying your likely supporters in a primary, we’ve seen that most primary campaigns focus mainly on persuasion.

Estimating who is most likely to vote in your election is pretty straightforward. And given the low turnout in most primaries, it’s usually not that daunting to cast a wide net with your outreach and attempt to reach nearly all likely voters.

But we believe persuasion targeting is not as straightforward as it might seem. Since turnout is often so low, there’s a real risk that you might be increasing the chances that people who are not going to support your campaign will go out and vote.

On the left, we love when all voters exercise their rights. But when you have limited resources, it’s not a good idea to put them toward increasing turnout among your opponents’ supporters. And we’ve seen that persuading the wrong people can do exactly this, meaning that your outreach might actually reduce your vote share.

Because of this, it’s very important that you focus your persuasion outreach on people with the highest chances of voting. Ideally, this means focusing on people with both high turnout scores and some history of voting in recent primaries.

Also, while campaigns will often filter out people with especially high or low support scores in a general election context, we don’t think that’s as necessary in primary elections. Support is more difficult to estimate in primaries. So if somebody has a high modeled support for your campaign, but their turnout score is high enough that they aren’t in your turnout universe, it could be a good use of your resources to verify & lock down their support.

What are you waiting for?

If you’re running a primary campaign, you need to start reaching the right voters ASAP. Deck is ready to help you do exactly that! Sign up now to start targeting your outreach and advertising to exactly the right people.

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