When comparing campaign data from ESPs with Yahoo's Performance and Placement Data, senders should expect similar but not necessarily the exact same results.

This is not because data from either source is wrong. ESPs and Yahoo have different levels of visibility and so measure data in slightly different ways.

Validity displays Yahoo’s Performance and Placement Data in conjunction with View Time Optimization (VTO) and with the Certification Program.

Placement Data tells senders whether an email reaches the inbox, is blocked at the gateway, or is filtered into the spam folder. Performance Data gives senders information on opens, clicks, and related measures of engagement.

Coverage by domain

Senders may want to isolate ESP data by domain to compare to Yahoo data. Looking only at yahoo.com and aol.com addresses, however, misses part of the story.

Yahoo’s Placement data reflects over 350 domains—all the locations where Yahoo operates or acts as the mailbox provider. The Yahoo brand, for example, includes not just yahoo.com but also yahoo.ca, yahoo.co.uk, yahoo.com.au, yahoo.fr and so on.

The primary domains of interest to most senders covered by Yahoo data are yahoo.com and aol.com. Yahoo data also covers domains for Verizon, Netscape, AT&T, and other smaller domains or partners using the Yahoo email infrastructure.

Coverage by country

The destination country for a sender’s campaigns (i.e., the recipient locations) may affect data reporting. 

Data privacy laws vary by country and jurisdiction. Not all privacy laws and terms of service allow for technology to report back on Performance and Placement Data.

Currently, Performance data (included with VTO) covers a set list of countries in North America, EMEA, and APAC. Yahoo is looking to expand Performance data reporting coverage in the future.

If a sender’s campaigns reach additional countries beyond the list above, only their ESP data will reflect counts for those countries at this time.

Inbox Placement

ESPs typically report the delivery rate, which only tells you the percentage of email the mailbox providers accepted for delivery. It does not tell you what percentage of the email went to the inbox or was placed in the spam folder.

Yahoo reports direct inbox and spam placement data. For inbox and spam placement at Yahoo domains, Placement data should be considered authoritative.

Additionally, ESPs and other sources (including Validity) use seed data for folder placement reporting. Seeds provide an excellent high-level understanding of your campaign’s deliverability. Seeds use sample emails sent to non-real users to estimate inbox placement. Yahoo Placement Data uses actual statistics from all mail sent to real users to provide an authoritative view of exactly where your mail was placed.

Time Zone

ESP data may be based on a different time zone from Yahoo data. Yahoo and Validity use UTC for reporting.

Opens

Many ESPs use pixel tracking to count opens. While pixel tracking is widely used, the data is approximate.

Pixel tracking data counts an "open" when an image in an email is retrieved from a server. However, some email applications retrieve images prior to delivering an email to a subscriber. This activity counts as an "open" even if the subscriber does not actually open the email.

Pixel opens are also not counted when an email application caches images on their own proxy server or when a subscriber opens an email with images suppressed.

ESPs can adjust open data if a link is clicked, but an email does not register an open. The ESP can count that interaction as an “implied open.”

Yahoo's open data is based on actual subscriber interactions within their mailbox and does not use pixel tracking. Senders can be confident the entire email message was displayed (opened) when using Yahoo’s Performance data open counts.

For additional information on pixel tracking data, please read:

Email open rates are actually up to three times lower than reported

Clicks

ESPs generally use one of two methods to count clicks. The data from these methods is more exact than pixel tracking data for opens.

• An ESP can create redirects for every link in an email, so a click is first routed through—and counted by—the ESP before redirecting to the destination link.
• A script can be placed on the destination website to count the click.

In this way, an ESP can track both total and unique clicks.

Not all clicks represent subscribers. Security companies may click one link or even all links in an email as part of their anti-malware efforts. This action is not unique to any one ESP but takes place industry-wide. It can be challenging for ESPs to determine when links are clicked by real users versus security checks.

Yahoo's Performance click data, like its open data, is based on interactions within the mailbox. Both real opens and clicks closely match Yahoo’s extrapolated data from initial models.

Like ESP data, Yahoo Performance data does not distinguish between subscriber clicks and security clicks. Performance data reports total clicks only at this time.