How to accurately measure email open rates without relying on image pixels or clicks?

Key findings

• Traditional tracking: Email open rates are conventionally measured by embedding a 1x1 tracking pixel. When the email client loads this image, it registers an open. However, this method is increasingly unreliable due to image blocking, pre-fetching by mailbox providers, and privacy features.
• Click tracking: Clicks on links within an email are generally considered more reliable indicators of engagement than opens, as they typically require a user action. Yet, they do not account for recipients who read the email but do not click on any links, or emails that are purely informational without calls to action.
• Privacy challenges: Features like Apple Mail Privacy Protection (MPP) pre-load all images, including tracking pixels, masking the true open event and inflating reported open rates. This makes it harder to accurately estimate real open rates.
• Bot interactions: Spam filters and security scanners often open emails and click links to analyze content, generating artificial engagement data. It's crucial to distinguish human versus bot email opens to get a true picture of engagement.

Key considerations

• Focus on alternative metrics: Given the unreliability of open rates, marketers should prioritize other engagement metrics such as click-through rates (CTR), conversion rates, reply rates, and website activity originating from email campaigns. Microsoft discusses rethinking email marketing metrics.
• Direct user action: For specific campaigns, encouraging direct replies (e.g., reply 'YES' to confirm interest) can serve as a qualitative measure of engagement, although it's not scalable for large volumes.
• Content design: Design emails to be effective even without images or clicks. Ensure the primary message is conveyed in plain text, providing value upfront.
• Server-side tracking: Explore server-side tracking solutions that might capture data before client-side image loading, though these still face limitations with privacy features and proxy opens.
• Holistic view: Combine various metrics to form a comprehensive understanding of recipient engagement. Relying on a single metric can be misleading. Consider what opens should be used as a metric.

Key opinions

• Clicks as reliable proxies: Many marketers view clicks as the most dependable indicator of actual engagement, especially when automated or spam filter clicks can be filtered out.
• No perfect alternative: The consensus is that there aren't many viable options beyond image loads or clicks to reliably measure if an email has been seen by a human recipient.
• User action is key: For any form of reliable tracking, a direct user action is generally required, whether it's loading an image or clicking a link. Without it, measurement becomes speculative.
• Encourage engagement: Marketers are increasingly focused on designing emails that drive tangible engagement, such as visits to a website, rather than solely relying on passive metrics like opens. Mailmodo discusses how to calculate your email open rates.

Key considerations

• Prioritize value: Ensure that the email's core message and value proposition are clear even if images are blocked or not loaded. This can be critical for protecting deliverability for image-only emails.
• Calls to action: Every email, regardless of its primary purpose (e.g., notifications), should ideally include some form of call to action or engagement point, to provide a measurable outcome.
• Text-only impact: While text-only emails might be read, their engagement can be difficult to quantify without images or links. This requires careful thought about whether all-image emails have higher open rates.
• Reply-based engagement: For specific campaigns or highly engaged segments, explicitly asking recipients to reply to the email can provide a direct, albeit manual, form of engagement tracking.

Key opinions

• Engagement over opens: Experts advise shifting focus from open rates to deeper engagement metrics like clicks, conversions, and replies, as these reflect more intentional recipient interaction. This supports the move towards alternative metrics to email open rates.
• Technical limitations: The fundamental reliance on image loading for open tracking means any technology that suppresses image display or pre-fetches content will inherently skew open rate data.
• Impact of MPP: Apple Mail Privacy Protection has significantly complicated open rate measurement, leading to inflated numbers and making it nearly impossible to determine genuine human opens for MPP-enabled users. This has raised questions like is email tracking dead?
• Spam filter activity: Automated systems that scan emails for malicious content or spam often trigger tracking pixels, generating false opens. This makes it crucial to identify artificial email opens.

Key considerations

• Attribution modeling: Implement more sophisticated attribution models that link email campaigns to downstream actions on websites or apps, providing a clearer view of email's impact.
• First-party data: Leverage first-party data (e.g., login activity, purchases, content consumption) to gauge engagement, as this data is directly controlled and not subject to email client limitations.
• A/B testing for engagement: Conduct A/B tests focused on optimizing click rates or conversion rates rather than just open rates, to drive more meaningful engagement.
• Sender reputation: Maintain strong sender reputation through consistent good practices, as this ultimately influences inbox placement, which is a prerequisite for any engagement measurement. Email on Acid offers a guide to increase email open rates.

Key findings

• Image pixel dependency: The foundation of most email open tracking systems is a small, often invisible, image embedded in the email. An open is registered when this image is downloaded by the recipient's email client. Email on Acid provides a good overview of tracking pixels in email.
• Client-side control: Whether an image loads is largely determined by the recipient's email client settings. Many clients block images by default, requiring the user to manually enable them, thus preventing accurate open tracking.
• Proxy pre-fetching: Mailbox providers often use proxy servers to pre-fetch email content, including images, to scan for security threats or to enhance user experience. This pre-fetching triggers the tracking pixel regardless of whether the user actually opened the email.
• Text-only emails: Emails composed entirely in plain text or where images are disabled will not trigger pixel-based open tracking, leading to an undercount of actual views. This affects alternative tracking for government emails.

Key considerations

• Shift to click metrics: Documentation often implies that clicks are a more robust metric for engagement. Links generally rely on server-side redirects, which are less susceptible to client-side privacy features.
• Server-side logging: While not a direct open metric, server-side logging of email delivery status (e.g., accepted by recipient server) provides data on whether an email successfully reached its destination, forming the foundation of deliverability measurement.
• User experience focus: Documentation encourages designing emails for optimal user experience first, with tracking as a secondary consideration. This means ensuring content readability and clear calls to action regardless of image loading.
• DMARC reports: For deliverability insights, DMARC aggregate reports provide XML data on email authentication results, which can indirectly indicate email acceptance rates by various receivers, although they don't track opens directly. This is a key aspect for understanding DMARC reports.