Zero-Party Data vs. First-Party Data: What's the Difference and Why It Matters in 2026

Zero-party data is information a customer intentionally shares with a brand, like preferences or survey answers. First-party data is information a brand observes from customer behavior, like purchases and browsing activity. Both matter in 2026, but for different reasons, and the strongest customer data strategies use them together.

TL;DR: What Is the Difference Between Zero-Party and First-Party Data?

Zero-party data is declared by the customer. First-party data is observed from the customer's behavior.

• Zero-party data comes from a customer directly telling a brand something, like a preference quiz
• First-party data comes from watching what a customer actually does, like a purchase history
• Safari and Firefox already block third-party cookies by default, making both data types more valuable
• 84.1% of consumers say they're concerned about data privacy when interacting with brands online
• Baesman's work with Kate Spade shows what first-party data can do for customer acquisition

What distinguishes zero-party data from first-party data?

The difference comes down to where the information originates. Zero-party data is handed over on purpose. First-party data is collected by observing what a customer does.

A customer who fills out a style preference quiz is generating zero-party data. A customer who buys the same product twice, without ever being asked about it, is generating first-party data. Both are collected directly by the brand, which is what separates them from third-party data bought from an outside source.

What Is Zero Party Data?

Zero party data is information a customer proactively and intentionally shares with a brand, rather than information inferred from their behavior.

Common examples include:

• Answers to a preference quiz or style profile
• Survey responses about product interests
• Communication preferences, like preferred channel or frequency
• Stated occasion or purpose for a purchase, such as a gift

Because the customer chooses to share it, zero-party data tends to be highly accurate. There's no guesswork involved in interpreting what it means.

What Is First Party Data?

First party data is information a brand collects directly by observing a customer's actions, such as purchases, website activity, or engagement with email and direct mail.

Unlike zero-party data, first-party data doesn't require the customer to say anything. It's built from a record of what actually happened: what they bought, how often they bought it, and which channels they responded to. Baesman's customer engagement strategy and analytics services are built around turning this kind of behavioral data into usable customer insight.

Why Does This Distinction Matter More in 2026?

The distinction matters more in 2026 because the data landscape brands can rely on has genuinely narrowed, just not in the way many marketers expected.

Third-party cookies haven't disappeared from Chrome the way the industry once predicted. But Safari and Firefox already block them by default, which means a meaningful share of the browser market has been effectively cookieless for years. That makes data a brand actually owns, whether declared or observed, more valuable than ever.

Consumer sentiment backs this up. According to Attest's 2026 Zero-Party Data Revolution report, 84.1% of consumers say they're concerned about data privacy when interacting with brands online. Notably, 48% of consumers say they'd rather share information through an interactive survey than have it collected through cookies, compared to just 18.8% who prefer the cookie route.

How Should Brands Use a Preference Quiz to Collect Zero-Party Data?

Brands searching for how to collect zero party data should start with a preference quiz, one of the simplest, most effective ways to gather it without feeling intrusive.

For example, a retailer might ask a new customer a few quick questions during signup: preferred product categories, sizing, or how often they want to hear from the brand. That customer immediately gets more relevant recommendations, and the brand gets accurate data it never had to infer.

A well-designed quiz should:

• Ask only a few questions, not a long survey
• Explain briefly why the information improves the customer's experience
• Feed answers directly into messaging, not just sit in a database unused

How Did Kate Spade Use First-Party Data to Drive Acquisition?

Baesman's work with Kate Spade shows what first-party data can do when it's actually put to use.

Kate Spade needed a better way to acquire new customers and turned to Baesman for a data-driven approach. The team compiled customer data from multiple sources into a single view, analyzed spending behavior, and built acquisition matchback logic to identify which customer types were actually worth pursuing.

The result: Kate Spade's customer acquisition performed 15% above plan. That lift came entirely from observed, first-party behavioral data, not from asking customers to fill out a form.

What Should a Zero Party Data Strategy Include?

A strong zero party data strategy treats the customer's willingness to share information as something to earn, not something to assume.

At minimum, it should include:

• A clear, low-friction way for customers to share preferences, like a short quiz or preference center
• A visible explanation of how that information will be used
• A process for actually acting on what customers share, not just storing it
• Regular opportunities to update preferences as they change

How Do Zero-Party and First-Party Data Work Together?

Zero-party and first-party data work best as complements, not substitutes. Zero-party data tells a brand what a customer wants. First-party data confirms what they actually do.

A customer might say in a preference quiz that they're interested in a specific product category. First-party purchase data then shows whether that stated interest turns into real behavior. Combining both gives a brand a far more complete, accurate picture than either one alone. Baesman's customer loyalty programs are built around exactly this kind of combined data, using both declared preferences and purchase history to shape what a member sees next across direct mail and email and SMS.

How Does This Connect to Broader Customer Segmentation?

Zero-party and first-party data are the raw material behind effective customer segmentation. Neither one means much without a strategy for organizing it into groups a brand can actually act on.

For a deeper look at how this data feeds into segmentation and where AI fits into that process, see Baesman's Customer Segments: How Brands Are Rebuilding Them for the AI Era. Coordinating that data across channels is what turns accurate data into a consistent customer experience.

What Should Brands Track to Measure Zero-Party and First-Party Data Success?

Brands should track whether collected data is actually improving relevance, not just growing in volume.

Useful metrics include:

• Preference quiz or survey completion rate
• How often declared preferences match observed purchase behavior
• Response rate lift when messaging uses zero-party or first-party data versus generic messaging
• Data freshness, or how recently a customer record was updated

Frequently Asked Questions About Zero-Party and First-Party Data

What is the main difference between zero-party and first-party data?

Zero-party data is information a customer intentionally shares, like preferences. First-party data is information a brand observes from behavior, like purchases.

What is zero-party data?

Zero-party data is information a customer proactively and intentionally provides to a brand, such as answers to a preference quiz or survey.

What is first-party data?

First-party data is information a brand collects directly by observing customer behavior, such as purchase history or website activity.

How do you collect zero-party data?

A short, low-friction preference quiz or survey is one of the most effective ways to collect zero-party data, especially when it's clear how the information will improve the customer's experience.

Why does the difference between zero-party and first-party data matter in 2026?

Safari and Firefox already block third-party cookies by default, and most consumers say they're concerned about data privacy, making data a brand collects directly, whether declared or observed, more valuable than ever.

Can zero-party and first-party data be used together?

Yes. Zero-party data shows what a customer says they want, and first-party data confirms what they actually do, giving brands a more complete and accurate view when both are combined.

Final Takeaway: Why Both Data Types Belong in Every Strategy

Zero-party and first-party data answer two different questions. One tells a brand what a customer wants. The other shows what a customer actually does. Neither replaces the other.

Brands that combine both see more relevant, accurate targeting than brands relying on just one, the same principle behind Kate Spade's 15% above-plan acquisition lift built on first-party behavioral data.

To see how Baesman can help turn zero-party and first-party data into a connected customer strategy, talk to Baesman.