Deliverability > Inbox Placement Factors Index

Deliverability Inbox Placement Factors Index

By Heath Weaver Updated May 1, 2024
Reviewed by Heath Weaver
Heath Weaver was Managing Director of Essence of Email and loves everything about email, sales & marketing, and running remote teams.
Full bio – Connect on LinkedIn
TABLE OF CONTENTS
What is the Deliverability Inbox Placement Factors Index?

What is the Deliverability Inbox Placement Factors Index (DIPFI)?

The Deliverability Inbox Placement Factors Index is similar to the work done in SEO to unravel the algorithms used by search engines.

All of the major inboxes have their own algorithm to determine which emails they accept or reject, which they put into spam. AI doesn't change that these algorithms are used, it just means far more data can be processed and the system can incorporate more factors.

The DIPFI, as far as I know, is the only attempt to try to be more systematic about deliverability, similar to what is being done by major SEO tools.
Key Takeaways
  • The Deliverability Inbox Placement Factors Index (DIPFI) is a systematic attempt to reverse engineer the algorithm used by the major inboxes.
  • The DIPFI tracks as many factors as can be factually included

Inbox Placement Factor Categories

The inbox placement factors can be categorized into seven major areas. Those areas are:

  • DNS Setup, Infrastructure, & Sender Reputation
  • Engagement
  • Mobile Optimization
  • Content
  • Mobile Optimization
  • Timing & Frequency
  • Personalization & Targeting

36 Inbox Placement Factors

  • IP Reputation: The score that your shared or dedicated IP address is given based on an inboxes past experience with emails from it, as well as any website reputation information.
  • Domain Reputation: The score that the domain address is given based on past experience, similar to the IP Reputation, but it is less important as it can be easily changed or spoofed.
  • SPF
  • DKIM
  • DMARC: Checking if your IP has a DMARC in place and if it has the information regarding your sending infrastructure. An improperly configured DMARC can result in almost all marketing email going directly to spam.
  • BIMI
  • Blacklist Presence: If your IP or domain are on any reputable blacklists it can have serious consequences.
  • Spam Trigger Words: While no longer very important, overuse of some words can have a negative impact.
  • Text-to-image Ratio:
  • HTML-to-text Ratio
  • Content Uniqueness
  • Open Rate
  • Click-through Rate
  • Bounce Rate
  • Hard Bounce Rate
  • Soft Bounce Rate
  • Spam complaint rate
  • Unsubscribe Rate
  • Forwards: As it is difficult to organically get people to forward your email to others so this is an important deliverability factor.
  • Marked As Favorite: Saving an email for later and then revisiting it is difficult to fake, so it is an important positive factor.
  • Replies: Replying to an email can be both positive and negative. People replying to stop receiving your emails can be a very negative factor, however replying with positive sentiment is difficult to fake and therefore a positive factor.
  • Add To Contacts/Address Book
  • Emails marked as read or deleted without being opened
  • List Acquisition Method
  • List Segmentation
  • List Hygiene
  • Spam Trap Hits
  • Time of Day
  • Day of Week
  • Send Frequency
  • Subject Line Personalization
  • Dynamic Content
  • Behavioral Targeting
  • Responsive Design
  • Pre-header Text
  • Alt Text For Images