As a marketer, understanding the difference between data types could be one of the most useful things you do this year, because data underpins almost every decision you make about who to reach, what to say, and whether it worked. Zero-party. First-party. Second-party. Third-party. Is it a data party? Probably not, but the good news is it's simpler than it sounds. Here's a cheat sheet for easy reference, that you can share with anyone who may find it useful.
Zero-party
Data people choose to share
This is data a person deliberately and proactively shares with a brand, think preference centres, quizzes, surveys, or simply telling a retailer they prefer email over SMS. Because the person hands it over willingly, it's the highest quality and most privacy-compliant data available. The catch? It requires building enough trust that people actually want to share. That makes it as much a brand challenge as a data one.
First-party
This comes directly from your own audience through your own channels, your website, app, CRM, loyalty programme, or purchase history. It's owned by you, highly accurate, and increasingly the most valuable asset a marketer can have. Woolworths Everyday Rewards is a classic example of a first-party data asset built at scale.
Zero vs first-party what's the real difference?
One is observed, one is declared. First-party tells you what someone does. Zero-party tells you what someone wants. If someone browses running shoes on your site, that's first-party, you infer they might be a runner. If they fill in a quiz saying they train three times a week for a half marathon, that's zero-party, they told you directly. Both have value, but zero-party removes the guesswork.
Second-party
A partner's data, shared directly
Someone else's first-party data, shared directly with you through a formal partnership. The key word is direct, it's not bought through a marketplace, it's agreed between two parties. Think of a media owner like NZME sharing audience data with a retail advertiser to target home renovation intenders. Both parties benefit, no broker involved. Less common, but highly relevant when the partner's audience closely matches yours.
Third-party
Bought data from brokers
Data collected by an entity with no direct relationship to the consumer, aggregated and sold through data brokers or exchanges. Historically this powered a large portion of digital targeting, but it's the most contested data type. Browser changes, shifting consumer expectations, and New Zealand's Privacy Act 2020 are all squeezing it. Its long-term utility is declining fast. Woolworths' investment in Everyday Rewards is a direct response to exactly this reality.
The marketers getting ahead right now aren't the ones with the most data. They're the ones with the best data, earned, owned, and built on real consumer relationships.
A useful starting point: do you know what first-party data you hold and whether you're using it well? Do you have any zero-party strategy, even a basic one? And if third-party data became unavailable tomorrow, how exposed would you be? There are no right or wrong answers, but knowing where you stand is the first step toward building something that lasts.
Three things you can do in the next 90 days.
1. Audit your first-party data
Most organisations hold more than they realise, CRM records, purchase history, email engagement, website behaviour and use far less of it than they should. Map what you have, where it lives, and whether it's connected. You can't build on what you can't see.
A post-purchase survey with two questions is achievable for almost any organisation. "What made you choose us?" and "What would make you buy again?" is zero-party data and more useful than most marketers realise. Keep it short; the moment it feels like a form, people leave. And skip the prize draw, it attracts people motivated by the reward, not a genuine relationship with your brand.
If you're a brand, ask your agency what data is powering your targeting and what their plan is as restrictions tighten. If you're an agency, make sure you can answer that question clearly and bring it to clients proactively. If you're a publisher, consider whether you're making it easy enough for partners to access your first-party data through clean, consented means.
So, that's the data. Hopefully we've demystified all the parties and you can get on with knowing more about the consumers you're marketing to.
Thank you to Adnan Khan, Co-Founder Sitch and Stitch Predict, and IAB New Zealand AI Working Group Lead, and Qassem Naim Founder Team Circle, Chair IAB New Zealand Data, Privacy and Measurement Council for spotting the need for this article and their contributions.