The open rate, and its related metrics, the click-through and unsubscribe rates, have become the holy yardsticks of email marketing campaigns and newsletters. The marketing trade press is full of case studies and how-to articles geared toward boosting open or click rates. No wonder everybody obsesses over these metrics.

However, they won't tell you if your campaign truly was successful or not. Most email-specific metrics are "process" metrics, which measure external aspects of a specific email campaign or delivery. Others are "output" metrics, which measure the goals you want to achieve, either in a single campaign or in your email program at large.

Process and output metrics measure different factors in your email campaign. You need to learn which metrics matter most for what you're trying to achieve with your email program. Once you learn the differences, you can build a framework of relevant metrics that will measure your campaign's outcomes.

Process vs. Output Metrics

Process metrics focus on the email message itself, such as the open and click-through rates, unsubscribes and bounces. Think of them as diagnostic tools. If you aren't seeing the results you want from your email campaigns, these metrics might help you spot problems with delivery, opt-in procedure or reader engagement.

These are typical process metrics, reported in each delivery but most useful when tracked over time to spot trends:

*Email Open rate: The percentage of delivered email messages opened by recipients. Tracked over time to measure customer interest or engagement.

*Email Bounce rate: The percentage of sent emails that failed delivery. Tracked to measure deliverability and list quality.

*Unsubscribes: The percentage of email messages that generated removal from your list, usually by recipients clicking an email link or a link to a Web unsubscribe page. Tracked to measure customer engagement.

*Email Click-through rate: The percentage of recipients who click on one or more links in the email. Measures customer interest, offer quality and engagement.

*Email Delivery rate: The percentage of total emails sent minus undeliverables. Used to measure deliverability and list hygiene.

*Spam complaints: Complaints that the message is spam, sent automatically by ISPs or manually by recipients. Usually expressed as a total number, not percentage.

*Referrals/forwarded messages: Expressed as a total number or a percentage of delivered emails, the number of times recipients clicked a forward-to-a-friend link in the email. Measures customer interest, word of mouth and offer quality.

"Output" metrics, on the other hand, measure the results of an email message. If you set goals for your campaign – say, a 15% increase in revenue per email or 500 new mailing-list subscriptions – these metrics will measure those and show you how close you came.

Some output metrics:

*Total revenue generated: The total revenue generated from the start to finish of the campaign.

*Revenue per email delivered: Total revenue divided by number of emails delivered. Used to compare different campaigns on offer quality or campaign effectiveness or progress toward goal.

*ROI per email: Measures return per email delivered. Used to compare results between campaigns or progress toward goal.

*Total orders per email: Total number of orders generated by email message.

*Order size per email: Total number of orders divided by number of delivered emails. Used to measure progress toward goal or to compare campaigns.

*Customer lifecycle steps: Measures successful efforts to upsell customer or to move customer through sales or life cycle.

*Leads generated: Total number of customer referrals or self-referrals generated by the email or over a period of time, e.g., 12 months. Measures offer quality and customer engagement.

*Site registrations, contest entries, subscriptions: Measures customer interest and engagement.

Build Your Email Marketing Framework

These eight steps will help you set up and implement a metric framework to use in measuring results:

1. Establish the key goals for your email program and campaigns – that directly support business/marketing objectives.

2. Choose the metrics that will measure those goals, while distinguishing between process and output metrics.

3. Make sure your email marketing software tracks the kinds of metrics you need most. If not, you might have to figure them manually or look for a third-party program to track them.

4. Set up the necessary reports.

5. Create a spreadsheet to collect and analyze the numbers. Use charts when possible to spot trends.

6. Compare results from testing, such as a classic A/B split on subject lines, content, offers. Also track results over time, highlighting highs, lows and averages or means.

7. Determine which goals you meet and which you miss most often.

8. Review each aspect of your email program for improvement.

Still Seeing Poor Performance?

If you're consistently missing a goal or seeing no improvement over several campaigns, these factors may be sabotaging your best efforts:

*Poor permission practices: This is one of the top drivers of weak results, especially if you collect names from dubious sources (buying names or acquiring through co-registration without a permission guarantee, using email appends, not confirming opt-ins).

*Incentivized subscribers: These subscribers sign up for your list through a sweepstakes, download or other come-on, not because they're interested in your email program.

*False expectations: You might be promising more in your opt-in promotions than you deliver in your mailings.

*Poor content or format: Your message content may look like spam or be hard to read. If you cram all the content into one giant image, readers who block images from downloading or read email in a preview pane will see nothing but a blank screen.

*Irrelevant email content: People's needs and interests change over time. A parent of a toddler doesn't need the baby-care advice she signed up for three years ago. You either need to diversify your email offerings or give users the ability to update their preferences or unsubscribe easily.

*Low email deliverability: You can't expect good results if 20% or more of your messages fail to reach your subscribers' inboxes. Check your delivery reports during and after each send to identify which ISPs may be blocking your emails or which addresses are failing. Make sure your email marketing software removes bouncing addresses and processes spam complaints.

*Wrong frequency: You might be sending too many emails and causing your subscribers to ignore you. Or, you don't send often enough, and they forget about you or find someone else who fits better. A preference page allows users to tell you how often they want to hear from you.

*Old email list: Names on a mailing list start to decay after three to six months, generating lower opens, clicks and conversions than newer names. You may need to contact older subscribers periodically, either to reinvigorate them or give them the chance to unsubscribe.

Two Closing Thoughts

Get buy-in from higher-ups. One reason why you must understand which metrics matter is that you'll eventually have to explain them to others in your organization, including your managers. Especially when it's time to ask for more resources or justify the money your company is spending on email marketing.

More metrics available. Once you get the basics down, you can start looking at alternatives that can give you even more precise measurements.

This list includes hurdle-rate metrics (how many subscribers you have to add to either maintain or grow list size, minus inactives and unsubscribes), the referral rate, your initial drop-off rate, orders per delivered emails, opt-in page conversions and the seeded delivery rate.