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We all know by now that somewhere out there exists a detailed profile of each of us based on a ton of data collected and aggregated by a few data companies. I think most of us understand that much of this data is acquired without our knowledge, but we just accept it. Kind of like how we just have to accept Ryan Seacrest broadcasting to us for the next 40 years.

We also know that this data is peddled by a handful of these companies to any marketer with a budget and thoughts on how to carve it up.

This data comes from an array of big brother-ish tactics such as examining your purchases at Walgreens, acquiring public records associated with you (marriage, home ownership), your browsing history, and through partnerships with traditional, and digital publishers (think Field and Stream, Forbes).

Side note: If you want to see what one of your big brothers thinks about you based on your browsing habits check this out.

This is third-party data. Third-party data is data that’s purchased to gain insight into voters/consumers. It’s information collected and aggregated by a single entity, which doesn’t have a direct relationship to the voter/consumer.

Campaigns use this data a bunch of different ways to target outreach across digital (often through a DMP), phones, doors, mail, and TV. So the question is: How reliable is it, and how much value can it bring to your campaign?

Data providers understand there’s something very appealing in what they’re offering. In theory, it’s highly granular and actionable insights on the voters you want to talk to, at scale (like as much as you want in, like, five minutes). What’s not to love?

I like to think of third-party data this way. It’s information that someone you don’t know is telling you they know, about someone you want to know (who they actually don’t really know). Lots of paths for that to go sideways.

A recent study by Deloitte highlighted many of the inaccuracies found in commonly available third-party data.

The bottom line is that is very difficult to accurately compile, and match back thousands of different data points to an individual. Emerging technologies like blockchain that give individuals control over their own data and what they are willing to make public could help, but this is years away.

The KISS Principle

Now, all is not lost. Third-party data should still be used in your campaign, so long as your expectations are in line with its actual value, and you keep it simple (KISS).

First of all, some data, including, gender, homeowner, veteran, gun owner, and age, is consistently more reliable.

Then there’s the voter file, arguably the mother of all third-party data when it comes to campaigns. Voter files contain 80 percent of all you need to know including party affiliation, when they’ve voted, postal and residential address and, in many states, phone numbers.

Generally speaking, voter files will be much more accurate than consumer data provided by companies like Axciom, BlueKai, and Lotome. The reason is pretty simple, each state has a standardized process as to how voter data is collected, aggregated, stored, and updated. Since the source is a government entity, there should be a higher level of trust considering there is a greater level of transparency.

Although purchasing voter files directly from states is generally inexpensive and easy, for most campaigns, getting it into a usable format is far from simple. Companies like L2 and Aristotle provide cleaned up versions of voter files which are available for purchase. These scrubbed files often include other demographic and consumer third-party data referenced above.

Separating The Good From The Bad

Not all third-party data is bad, but some attributes could be consistently bad, and the only way to know for sure would be to ask the voter. But when you think about it, isn’t that why you bought it in the first place? So you didn’t have to ask the voter?

Personally verifying third-party data from a voter would be like bringing your own food to a restaurant and then ordering off the menu.

Although voter files are still aggregated by states from counties and towns, the data is generally cleaner, and more reliable than third-party sources. It’s where every campaign usually starts, and that isn’t likely to change anytime soon.

Justin Gargiulo is the founder and CEO of VoterTrove, a data management platform.