The following is the second installment of the subject line tips series. In this article Thane Stallings, Director, Strategic & Analytic Consulting Group, Epsilon, discusses 11 subject line mistakes that marketers often make. The article also includes best practice tips and explains why subject line testing is a crucial part of the process.

Listed below are the 11 mistakes and the best practices from that study:

1. Implementing “best practices” without first testing them. Don’t take anyone’s word about what works. Test, test, test! Best practices are a great resource for generating ideas, but they shouldn’t be adopted by your program without testing their influence on your specific situation first.

 2.   Failing to utilize every testing opportunity or only testing “important” campaigns. Every time you deploy an email is an opportunity to learn something about your customers and your email program. Sure, it can be difficult to test a subject line in the beginning, but it’s a worthwhile opportunity to learn something new and improve response.  

 3. Writing the subject line as an afterthought. Subject lines are often the last thing companies think about before sending out emails. But they are either the first or second thing recipients spot in their inbox. Ideally, subject line development should be built into a company’s deployment calendar to ensure the exercise doesn’t fall to the wayside.

 4. Failing to test principles. Knowing what subject line performs best for a particular campaign may not necessarily help you with the next one. Think of the big picture. Test different ideas. Testing principles means repeatable success.

 5. Testing multiple factors inside one test. If you test multiple factors inside one test, how will you know what one was successful? Testing multiple variants will likely create problems, causing you to walk away and not understand what you learned. Test one thing at a time so you can adequately compare your results and know what worked well.

 6. Using rules of thumb for sample size. Most of us are content to let our college statistic text book gather dust on the shelf. But statistics are something that can’t be ignored.  The reality is there is no one right answer for how large our testing groups (also called sample sizes) should be. To decide the size of a test group you can download a free statistics calculator from the Web.

 7. Hedging your bets. Subject lines should be vetted through a test group, and then the winner should be sent to the remainder of the audience. This is the “testing” in subject line testing. Marketers must first deploy a subject line test to a small audience (one large enough that still allows for statistically significant results) then send the winning subject line to the rest of the email file. Maximizing the size of the audience that gets the winning subject line maximizes your response rates.

8. Using the wrong metric. Don’t assume that more opens will translates into more clicks, and that more clicks will translate into more revenue. Sometimes a particular subject line will drive one metric, whereas a different subject line will drive another. When possible, use the metric you really care about as your success metric.

9. Neglecting to track findings. Companies that don’t track what they tested, at what time, and what worked are missing the boat. Additionally, that information can be used for other purposes, such as internal and external training, re-testing programs, starting a new email program or helping a different brand.

10. Taking results out of context. Outside influences, such as seasonality, time of day, competition or world events, can hamper an otherwise clean test. Be careful with your conclusions. If the results don’t seem to make sense, re-test to be sure. Accuracy is paramount.

11. Being impatient. If you’re just starting a subject line testing program, it’s going to take some time to work out the kinks. Be patient and learn from your mistakes. Each successive test may improve response by a couple of percentage points.

Read the full study at the Email Institute blog.
http://www.emailinstitute.com/premium/subject-line-tips?pid=EI2011-01-05