Email Deliverability Metrics: What to Track and Why

Email deliverability metrics are critical indicators of the health and performance of your email marketing campaigns. By closely monitoring and analyzing key deliverability metrics, you can identify potential issues, optimize your email strategy, and ensure your messages reach your subscribers' inboxes. This comprehensive guide will dive deep into the essential email deliverability metrics to track, explaining why they matter and how to leverage them for improved email performance and inbox placement.

Understanding Email Deliverability

Email deliverability refers to the ability of your emails to successfully reach your subscribers' inboxes. It encompasses various factors, such as sender reputation, email authentication, content quality, and subscriber engagement. Poor deliverability can lead to emails being filtered into spam folders or blocked entirely, hindering the effectiveness of your email marketing efforts.

Did you know? According to a study by Return Path, an average of 20% of commercial emails never reach the intended recipients' inboxes.

The following diagram illustrates the journey of an email from the sender to the recipient's inbox, highlighting the key factors that influence deliverability:

Key Email Deliverability Metrics to Track

To maintain a strong email deliverability rate and optimize your email campaigns, it's crucial to monitor and analyze the following metrics:

1. Bounce Rate Critical

Bounce rate measures the percentage of emails that fail to reach the recipients' inboxes. There are two types of bounces:

Hard Bounces: Permanent delivery failures due to invalid, closed, or non-existent email addresses. High hard bounce rates can severely impact sender reputation.
Soft Bounces: Temporary delivery failures caused by full mailboxes, server issues, or other transient problems. Soft bounces are less severe but still require monitoring.

Here's an example of how to calculate your bounce rate:

Bounce Rate Formula

Bounce Rate = (Number of Bounced Emails / Total Emails Sent) x 100

Example: If you sent 10,000 emails and 500 bounced, your bounce rate would be (500 / 10,000) x 100 = 5%

Best practices to minimize bounce rates:

Regularly clean your email list by removing invalid and inactive addresses
Use double opt-in to ensure subscribers intentionally sign up
Promptly remove hard bounces from your list

2. Delivery Rate Important

Delivery rate measures the percentage of emails that successfully reach recipients' inboxes or spam folders. It excludes bounced emails from the calculation. A high delivery rate indicates that your emails are passing initial spam filters and authentication checks.

The following diagram illustrates the factors that influence email delivery rate:

To calculate your delivery rate, use this formula:

Delivery Rate Formula

Delivery Rate = (Number of Delivered Emails / Total Emails Sent) x 100

Example: If you sent 10,000 emails and 9,500 were delivered (including those in spam folders), your delivery rate would be (9,500 / 10,000) x 100 = 95%

To improve your delivery rate:

Implement email authentication protocols (SPF, DKIM, DMARC)
Maintain a good sender reputation by following best practices
Regularly monitor and remove inactive subscribers

3. Inbox Placement Rate Advanced

Inbox placement rate (IPR) measures the percentage of delivered emails that land in recipients' main inboxes, rather than spam or junk folders. It provides a more accurate picture of deliverability than the delivery rate alone.

The following diagram shows the different possible placements for delivered emails:

Calculating IPR can be challenging, as it requires access to data from major email providers. Some email service providers (ESPs) offer inbox placement tracking tools, or you can use third-party services like 250ok or Return Path.

To optimize your inbox placement rate:

Maintain a high sender reputation through consistent, engaging email content
Encourage subscribers to add your email address to their contacts or safe sender list
Regularly monitor and resolve spam complaints

4. Open Rate Important

Open rate measures the percentage of delivered emails that are opened by recipients. It provides insights into the effectiveness of your subject lines, sender name, and preview text in enticing subscribers to open your emails.

Here's the formula to calculate your open rate:

Open Rate Formula

Open Rate = (Number of Unique Opens / Number of Delivered Emails) x 100

Example: If 9,500 emails were delivered and 3,000 were opened, your open rate would be (3,000 / 9,500) x 100 = 31.6%

Note: Open rates can be affected by factors like image blocking and Apple's Mail Privacy Protection, which can inflate the numbers.

Tips to improve your open rates:

Craft compelling, personalized subject lines
Optimize your sender name and preview text
Segment your email list and tailor content to each segment

5. Click-Through Rate (CTR) Critical

Click-through rate measures the percentage of recipients who clicked on one or more links within your email. It indicates the relevance and effectiveness of your email content and calls-to-action (CTAs).

The following diagram illustrates how CTR fits into the email engagement funnel:

Calculate your CTR using this formula:

Click-Through Rate Formula

CTR = (Number of Unique Clicks / Number of Delivered Emails) x 100

Example: If 9,500 emails were delivered and 1,000 unique clicks were recorded, your CTR would be (1,000 / 9,500) x 100 = 10.5%

To boost your CTR:

Create targeted, relevant content for each segment of your email list
Use clear, compelling CTAs that inspire action
Optimize your email design for easy navigation and mobile responsiveness

6. Unsubscribe Rate Advanced

Unsubscribe rate measures the percentage of recipients who opt out of your email list after receiving a campaign. While some unsubscribes are normal, a high unsubscribe rate may indicate issues with your email content, frequency, or targeting.

Here's how to calculate your unsubscribe rate:

Unsubscribe Rate Formula

Unsubscribe Rate = (Number of Unsubscribes / Number of Delivered Emails) x 100

Example: If 9,500 emails were delivered and 95 people unsubscribed, your unsubscribe rate would be (95 / 9,500) x 100 = 1%

To minimize unsubscribes:

Set clear expectations during the opt-in process about email frequency and content
Provide valuable, relevant content that aligns with subscribers' interests
Offer preference centers allowing subscribers to control email frequency and topics

7. Spam Complaint Rate Critical

Spam complaint rate measures the percentage of recipients who mark your emails as spam. High spam complaint rates can severely damage your sender reputation and lead to deliverability issues.

Calculate your spam complaint rate using this formula:

Spam Complaint Rate Formula

Spam Complaint Rate = (Number of Spam Complaints / Number of Delivered Emails) x 100

Example: If 9,500 emails were delivered and 19 spam complaints were received, your spam complaint rate would be (19 / 9,500) x 100 = 0.2%

Warning: Aim to keep your spam complaint rate below 0.1% to maintain a good sender reputation.

To reduce spam complaints:

Only send emails to subscribers who have explicitly opted in
Provide clear unsubscribe links and honor opt-out requests promptly
Avoid using spam trigger words and deceptive subject lines

Monitoring and Analyzing Email Deliverability Metrics

To effectively track and improve your email deliverability, follow these best practices:

Choose an ESP that provides robust deliverability features, such as automated bounce handling, feedback loop monitoring, and reputation management tools. Some popular ESPs with strong deliverability support include Mailchimp, Campaign Monitor, and Constant Contact.

Implement SPF, DKIM, and DMARC authentication to prove your identity to email providers and reduce the risk of your emails being flagged as spam. Work with your IT team or ESP to properly configure these protocols.

Use your ESP's analytics dashboard or third-party tools to track key deliverability metrics like bounce rate, delivery rate, inbox placement rate, and spam complaint rate. Set up alerts to notify you of any sudden changes or anomalies.

Regularly review your email content to ensure it is relevant, engaging, and aligns with best practices. Use A/B testing to optimize subject lines, CTAs, and layouts for better open and click-through rates.

Regularly remove bounced, unengaged, and inactive subscribers from your email list. Use email validation tools to identify and correct invalid or misspelled email addresses.

Case Study: Improving Email Deliverability at XYZ Company

XYZ Company, an e-commerce retailer, was struggling with poor email deliverability, resulting in low open rates and sales. By implementing the following strategies, they were able to significantly improve their deliverability metrics and overall email performance:

Implemented double opt-in to ensure a high-quality email list
Set up SPF, DKIM, and DMARC authentication protocols
Segmented their email list based on subscriber engagement and interests
Optimized email content and subject lines