What campaigns really do with your voter file
Matthew Durden on how state records become rich profiles, who gets access, and what you can do to protect yourself
“You need to recognize that your data is doing a lot more work on behalf of the campaigns than you are.” — Matthew Durden
Picture two neighbors, same ballot, same street — but each is fed a different set of engineered messages. Neither knows the other exists. Neither knows that the chain started when they registered to vote. That image is the spine of what Matthew Durden walked me through: how a public voter record becomes a scored, enriched profile used to target, persuade, and, sometimes, leak.
What gets added to the state file
The state file is simple on paper: name, home address, sometimes phone and email, license numbers, and turnout history. Once a broker gets it, things change fast.
Matthew describes an enrichment stack: contact matches (especially cell numbers and emails), demographic bands (age, household composition, modeled ethnicity), then consumer signals — credit-card transactions, parcel records, online activity. Those enrichments turn a voter record into a marketing profile with hundreds — brokers sometimes work up to 1,800 fields — of inferred traits.
A few concrete fields he named: partisanship or turnout scores (0–100 style numbers indicating likelihood to vote), modeled religiosity (down to probable church attendance based on travel patterns), home-ownership and estimated home value (parcel records are public), and household income (inferred from mortgage or credit applications, not a perfect number but repeatedly reinforced by your commercial footprint).
The key technical point: most of this is probabilistic. A broker stitches together records by address, purchase behavior and longitudinal traces. It’s rarely a 100% match, but it’s good enough to guide persuasion.
“Those assumptions will stick with you. There’s no real way for the consumer to see what their voter file looks like.” — Matthew Durden
Who touches the file and what they write back
Campaigns pull a “universe” — a list of people worth spending time and money on — from that enriched file. Universes are built to be cost-effective: isolate persuadable or high-propensity voters, then push resources there. The purchased extract that lands on a field director’s desk is typically name, address, phone, email, precinct info, language preference, and whatever score buckets the campaign licensed.
Every interaction with a voter can then be written back: support rating, interest in an issue, whether someone asked not to be contacted, or free-text canvass notes (“elderly, lives alone,” “aggressive dog,” or “likely supporter”). Campaigns use those notes to retarget — more mail, more texts, different social ads.
Crucial and uncomfortable detail: the enrichments from campaigns don’t die with the election. Per Matthew, the contractual model with brokers means the parent file is continually enriched by every campaign that touches it. Your “do not knock” note might exist only as a courtesy flagged on a canvasser’s device; the rest feeds the broker’s persistent profile.
Where the leaks happen (the wild west)
This part gets ugly. Campaign operations are resource-constrained and fast-moving. Volunteers and interns do the heavy lifting. That means: lists are downloaded to volunteers’ phones and tablets, often cached offline for canvassing, and frequently shared across many users.
Matthew’s audit checklist is telling: one login shared across dozens of users, no multi-factor, vendor accounts with no clear owner, apps left on phones after volunteers leave. CSVs exported from platforms are unencrypted spreadsheets with up to 1,800 fields — a single lost or reused device is a full-data breach waiting to happen.
He was blunt: campaigns rarely prioritize security because it “slows down the program.” The practical outcome is obvious: a volunteer can walk away with the entire dataset and repurpose, sell, or leak it.
What you can actually do as a voter
There’s no single silver bullet, but Matthew and I landed on three practical moves that matter now:
Request a copy of your state voter file so you can see what’s been recorded about you. Visibility is the first defense.
Make yourself expensive to profile. Reduce commercial leakage: limit merchant profiling, opt out where possible, and be stingy with sharing income and payment details online. The harder you are to stitch together, the less precise the enrichments.
Use address confidentiality programs if you’re eligible. States offer these to protect people; they should be more accessible and broader, and you can push your policymakers to expand them.
Matthew also emphasized a baseline stance: assume your registration is public and will be enriched, then act to mitigate downstream risks. That changes the mental model from denial to preparation.
The political and security implication to remember
This isn’t about red or blue. As Matthew said early on, every side runs the same machine. What matters is the mechanics: persistent enriched profiles, broad access inside campaigns, and a near-zero security posture in many operations. Those three together are what make targeted persuasion so precise — and what makes these files attractive to leak or abuse.
Understand that campaigns and brokers are building a living profile on you. Ask yourself whether you want to be the low-hanging fruit.
If you want the full conversation — we trace the enrichment chain, the canvass apps, and the specific examples that made me wince — listen to the full episode. Or start by pulling your voter record from your state office and see what’s already been written about you.