Zero-party data. First-party data. Second-party data. Third-party data. Is it a data party?
Unfortunately not. But if you work in marketing, understanding the difference between these four terms could be one of the most useful things you can do right now - because data underpins almost every decision you make about who to reach, what to say, and whether it worked.
The good news is it is simpler than it sounds. Here is your cheat sheet.
Zero-party data
This is data a person deliberately and proactively shares with a brand. Think preference centres, quizzes, surveys, or a customer telling a retailer they prefer email over SMS. Because the person hands it over willingly, it is the highest quality and most privacy-compliant data available. It requires building enough trust that people want to share - which makes it as much a brand challenge as a data one.
First-party data
Data you collect directly from your own audience through your own channels - your website, app, CRM, loyalty programme, or purchase history. The person has a relationship with you, and their behaviour generates this data. It is 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.
But Zero-party data and first-party data feel similar right? So what’s the difference?
The practical difference is one is observed and one is declared. First-party data tells you what someone does. Zero-party data tells you what someone wants. Both are valuable - but zero-party data removes the guesswork.
A simple example: if someone browses running shoes on your website, that is first-party data - you infer they might be a runner. If they fill in a quiz saying they run three times a week and are training for a half marathon, that is zero-party data - they told you directly.
Which is more valuable? Well that depends. Data explicitly shared reveals intent and perceptions, while observed behaviours show what they are actually doing, and actions can speak louder than words.
Second-party data
Someone else’s first-party data, shared directly with you through a formal partnership. The key word is direct - it is not bought through a marketplace, it is agreed between two parties. Think of a media owner like NZME sharing audience data with a retail advertiser to target home renovation intenders for a campaign - both parties benefit, no third-party broker involved. Less common than other data types, but highly relevant when the partner’s audience closely matches yours.
Third-party data
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. It is the most contested data type - increasingly restricted by browser changes, consumer expectations, and in New Zealand, the Privacy Act 2020, which places clear obligations on how personal data is collected and used. The long-term utility of third-party data is declining fast, and the shift is already visible locally: the investment Woolworths has made in Everyday Rewards as a first-party data asset is a direct response to this reality.
What this means for your marketing
The marketers winning right now are not the ones with the most data. They are the ones with the best data - earned, owned, and built on real relationships. A useful starting point is a simple self-assessment: do you know what first-party data you currently hold and whether you’re using it well? Do you have any zero-party data strategy, even a basic one? And if third-party data became unavailable tomorrow, how exposed would your targeting be? There are no right or wrong answers - but knowing where you stand is the first step toward building something that lasts.
What this means for your marketing
The marketers getting ahead right now are not the ones with the most data. They’re the ones with the best data - earned, owned, and built on real consumer relationships.
3 things you can do in the next 90 days to get your data party started:
1. Audit what first-party data you actually have
Most organisations hold more than they realise e.g. CRM records, purchase history, email engagement, website behaviour - and they use less of it than they should. Map what you have, where it lives, and whether it’s connected because you can’t build on what you can’t see.
2. Run one zero-party data experiment.
A post-purchase survey with two questions is achievable for almost any organisation. Something as simple as "what made you choose us?" and "what would make you buy again?" is zero-party data - and more useful than most marketers realise. Post-purchase works well because the relationship is warm and the person is already engaged.Keep it to one or two questions. The moment it feels like a form, people leave.On incentives: resist the instinct to offer a prize draw. It drives volume but attracts people motivated by the reward rather than a genuine relationship with your brand.
3. Have the third-party data conversation with whoever is closest to it.
If you're a brand, ask your agency what data is powering your targeting and what their plan is as third-party data becomes more restricted. If you're an agency, make sure you can answer that question clearly and that you're proactively bringing it to your clients rather than waiting to be asked. 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 their contributions to this article.