Match Rate Alone Isn’t Enough—Here’s Why Reach Rate Matters

The concept of match rate in the advertising ecosystem is not new. It’s a well-established metric that serves as an indicator to gauge how well an audience can scale within a platform. The match rate refers to the percentage of audience records that can be linked to identifiers, allowing a DSP to recognize them as a potential targetable audience. For example, if an advertiser has 1M users as their target audience, and the match rate is 50%, only 500k of the records potentially can be found in the given platform. 

Even though the match rate is generally considered a standardized metric, it can still vary across platforms. This is because different platforms manage different types of data, use their own logic behind the calculation and, in some cases, choose the methodology that produces the most favorable results for themselves.

For example, understanding the type of data the platform is using is important. In the past, third-party cookies and device IDs were the primary identifiers used in the matching process. However, with evolving privacy regulations and signal loss, hashed email addresses have now emerged as the standard matching identifier that is future-proofed to industry changes.

Given these variations, it’s crucial to understand how your partners define match rate and ensure the data they use is future-proof for long-term scalability. Additionally, match rate shouldn’t be the only metric you rely on. Another valuable metric to consider is the reach rate, which represents the actual biddable opportunities available from an audience within a platform.

Why is the reach rate important?

A high match rate does not guarantee that an audience is truly reachable. In our earlier example of an advertiser with 1M users, a 50% match rate only indicates an estimate of potential reach—not actual targeting ability. This is where reach rate becomes critical. While often lower than match rate, reach rate reflects the real, biddable opportunities within a platform, providing a more accurate measure of audience scalability and campaign effectiveness.

Some platforms intentionally inflate match rates—knowing advertisers often equate them with better reach—even when actual reach rates are significantly lower. Since there’s little incentive for these platforms to provide more accurate match rates, they may overlook key hygiene factors, such as proper identity resolution and active user definitions. This creates a misleading perception of scale while limiting real impact. That’s why evaluating reach rate alongside match rate is essential to understanding a platform’s true effectiveness.

Additionally, platforms with low reach rates often struggle with frequency capping, repeatedly targeting the same audience to exhaust the budget and ultimately leading to poor user experiences.
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Key Considerations for Evaluating Reach Rate

Just as with match rate, reach rate can vary significantly across platforms. To make an informed decision, advertisers should assess key factors that impact reach rate:

1. Do they resolve identities at the user level? Reach rate is a more valuable metric than match rate because it reflects people-based targeting rather than just email addresses or other disparate identifiers. For example, if a partner sends four different email addresses for the same user and only one is matched, the email match rate would be 25%, but the user match rate would be 100%. Resolving at the individual level allows for more accurate targeting, measurement, and frequency capping.
2. How do they define active users? Different platforms have different definitions of active users, which can impact targeting accuracy. Some remove users who haven't been active for the past 90 days, while others consider users active for up to a year or more. Since there’s no universal standard, it can differ significantly between platforms, which could impact your campaign targeting and effectiveness.
3. Do they prioritize consumer choice and privacy? In today’s privacy-first landscape, it's essential to work with partners that honor user preferences. Does the platform have robust opt-out mechanisms? More importantly, do they extend opt-outs across all associated devices, ensuring that a user’s privacy choices are fully respected? Prioritizing privacy-conscious platforms helps build consumer trust while ensuring compliance with evolving regulations.

While match rate remains a valuable benchmark, it should not be the only metric advertisers rely on. Reach rate provides a more accurate measure of real targeting opportunities, making it a crucial factor in evaluating a platform's effectiveness.

To maximize campaign success, advertisers should go beyond surface-level metrics, test with their partners, and ask the right questions. By prioritizing user-level resolution, active user definitions, and privacy safeguards, brands can make more data-driven, future-proof decisions in their advertising strategies.