Analysis: Best v. Worst Email Subject Lines
July 2013 -- Email marketing firm Adestra, analyzed the subject lines from over 2.2 billion marketing emails to discover keywords and phrases that customers respond to better than most, as well as ones are over-used and ineffective by sector.
The study, 2013 Adestra Subject Line Analysis Report: Keywords for killer subject lines, scores keywords by open, click, click-to-open, and unsubscribe rates for B2B and B2C publishing and more (events, non-profits).
Adestra warns report readers "your lists may respond differently to the long-run averages in their follo. However, at the very least (the) report will give you some ideas on what you should be testing on a campaign-by-campaign basis, and will help develop a robust and profitable subject line strategy. Individual campaign results will vacillate wildly from excellent to awful and all points in between; the key is to focus on a long-term subject line strategy and this report is (a) how-to-guide."
UNDERSTANDING THE RESULTS
For each keyword, the charts show the average deviation from the mean for campaigns with subject lines including that keyword.
To illustrate: If an industry average open rate is 20%, and the word “xyz” shows 12% higher opens, that means that inclusion of the word “xyz” in a subject line delivered a 22.4% open rate (a 12% increase, or lift, on 20%.)
EMAIL SUBJECT KEYWORD RESULTS
- Looking at the OVERALL chart, the word “Newsletter” shows a marginal effect on email open rates (+0.7%), but a strong negative effect on click rates (-18.7%.) Adestra states that this should be of no surprise – the word “newsletter” reflects back to the day of receiving a paper or PDF newsletter was the standard for getting out the latest news.
- Take the word “Alert,” which shows +38.1% opens and +61.8% clicks on the OVERALL chart. The word “alert” connotes something that is happening now and incites a sense of urgency in readers. The same can be seen with the word “Bulletin” (+15.8% opens, +12.7% click).
- "Content Marketing," says Alestra, "has oversaturated customers, both B2B and B2C, with too much information. For example, “Report” (-23.7%, -54.8%,) “Learn” (-35.5%, -60.8%,) and “Book” (-4.6%, -25.4%) are trending downwards.
- Communications that are sent out “Daily” (+27.8%, +100.3%) and “Weekly” (+27.1%, +50.6%) perform strongly. Alestra opines that this is because customers/readers begin to expect your emails on a frequent basis, and get into the habit of reading them.
- The statistics also show the possibility of saving money is a motivator. For example, offering “Free Delivery” (+50.7%, +135.4%) or specifying a percentage off in the subject line (+10.5%, +27.4%) are effective in getting readers to open marketing messages received.
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OVERALL RESULTS Keyword table |
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|
Keyword |
Open rate variance |
Click rate variance |
Click to open rate variance |
Unsubscribe rate variance |
|
Benefits |
|
|
|
|
|
Exclusive |
12.3% |
-0.3% |
-11.2% |
22.0% |
|
Free |
-3.0% |
-6.3% |
-3.3% |
-1.3% |
|
Free delivery |
50.7% |
135.4% |
56.3% |
82.4% |
|
Gift |
12.4% |
-11.3% |
-21.1% |
21.2% |
|
Latest |
8.3% |
11.7% |
3.1% |
-9.9% |
|
New |
17.2% |
38.2% |
17.9% |
-2.6% |
|
Offer |
7.3% |
-18.6% |
-24.1% |
22.3% |
|
Only |
-4.1% |
-37.3% |
-34.7% |
11.9% |
|
Sale |
23.2% |
60.7% |
30.5% |
31.6% |
|
Save |
3.4% |
-25.2% |
-27.7% |
18.1% |
|
Voucher |
20.0% |
-2.4% |
-18.7% |
60.6% |
|
Content |
||||
|
Alert |
38.1% |
61.8% |
17.2% |
-63.2% |
|
Bulletin |
15.8% |
12.7% |
-2.6% |
-22.9% |
|
Issue |
10.8% |
10.4% |
-0.4% |
29.6% |
|
Learn |
-35.5% |
-60.8% |
-39.2% |
-23.9% |
|
News |
34.8% |
47.7% |
9.6% |
-26.0% |
|
Newsletter |
0.7% |
-18.7% |
-19.2% |
2.9% |
|
Report |
-23.7% |
-54.8% |
-40.8% |
-54.6% |
|
Today |
-15.9% |
-37.9% |
-26.1% |
5.2% |
|
Video |
18.5% |
64.8% |
39.0% |
-26.0% |
|
Webinar |
-16.6% |
-70.7% |
-64.8% |
8.8% |
|
Win |
1.8% |
26.7% |
24.4% |
-2.9% |
|
Date |
||||
|
Daily |
27.8% |
100.3% |
56.7% |
-75.0% |
|
Monthly |
-26.6% |
-37.0% |
-14.2% |
13.8% |
|
Weekly |
27.1% |
50.6% |
18.5% |
-49.8% |
|
Call to action |
||||
|
Download |
1.4% |
-6.1% |
-7.4% |
-28.2% |
|
Get |
-8.6% |
-16.1% |
-8.2% |
2.5% |
|
Register |
-9.6% |
-54.9% |
-50.1% |
27.7% |
|
Subscription |
5.0% |
-19.1% |
-23.0% |
89.3% |
|
Urgency |
|
|
|
|
|
Don't miss |
-8.8% |
-42.9% |
-37.3% |
33.2% |
|
Miscellaneous |
||||
|
iPad |
31.6% |
19.9% |
-9.0% |
19.1% |
|
Re: |
-3.7% |
-42.6% |
-40.4% |
90.8% |
|
Fw: |
-14.3% |
-47.5% |
-62.8% |
135.4% |
|
Source: Alestra, 2013 |
||||
B2B PUBLISHING EMAILS
- For B2B publishers, emails with content subject keywords, "Breaking," and "Alert," performed best. "Forecast," and "Report," performed less well.
- For subscription marketing messages, "Trial," is a top performer.
|
B2B PUBLISHING Keyword Table |
||||
|
Keyword |
Open rate variance |
Click rate variance |
Click to open rate variance |
Unsubscribe rate variance |
|
Content |
||||
| Multiple stories “Headline 1 | Headline 2 |” |
27.5% | 90.7% | 14.2% | -8.0% |
|
Alert |
32.9% |
35.7% |
2.1% |
-45.5% |
|
Breaking |
35.4% |
77.6% |
31.2% |
-65.8% |
|
Editor |
28.7% |
68.3% |
30.7% |
-15.5% |
|
Forecast |
-34.0% |
-68.3% |
-51.9% |
-37.9% |
|
Issue |
6.9% |
-4.8% |
-11.0% |
69.1% |
|
Latest |
-2.0% |
-8.7% |
-6.8% |
17.1% |
|
News |
20.5% |
13.9% |
-5.4% |
-20.0% |
|
Newsletter |
-11.2% |
-52.6% |
-46.7% |
48.5% |
|
Report |
-30.6% |
-64.1% |
-48.3% |
-43.7% |
|
Top stories |
-11.2% |
-30.5% |
-21.7% |
-0.3% |
|
Update |
26.8% |
8.9% |
-14.1% |
-5.7% |
|
Date |
||||
|
This week |
-18.5% |
-28.6% |
-12.3% |
5.6% |
|
Daily |
12.6% |
35.8% |
20.7% |
-51.2% |
|
Weekly |
27.5% |
24.7% |
-2.2% |
-26.5% |
|
Monthly |
-6.4% |
-19.1% |
-13.6% |
134.6% |
|
Subscriptions |
||||
|
Access |
2.9% |
-7.3% |
-9.9% |
80.6% |
|
Free |
3.0% |
-8.4% |
-11.1% |
64.9% |
|
Renew |
0.6% |
22.6% |
-21.9% |
175.6% |
|
Subscription |
-8.2% |
-22.7% |
-15.8% |
266.7% |
|
Trial |
8.8% |
-6.6% |
-14.1% |
13.8% |
|
Source: Alestra, 2013 |
||||
B2C PUBLISHING EMAILS
- For B2C publishers, emails with content subject keywords, "Review," and "Update," and "Video," performed best.
- For marketing emails promoting sales, "Discount," seems a turn off.
|
B2C PUBLISHING Keyword table |
||||
|
Keyword |
Open rate variance |
Click rate variance |
Click to open rate variance |
Unsubscribe rate variance |
|
Content |
||||
|
Exclusive |
11.3% |
-1.2% |
-11.2% |
3.7% |
|
Newsletter |
6.4% |
16.5% |
9.5% |
3.8% |
|
Review |
37.1% |
152.3% |
84.0% |
-66.5% |
|
Special |
12.2% |
-12.1% |
-21.7% |
82.7% |
|
Update |
29.0% |
6.7% |
-17.3% |
141.2% |
|
Video |
27.6% |
96.6% |
54.1% |
-39.8% |
|
Win |
-2.3% |
18.3% |
21.1% |
-5.8% |
|
Date |
||||
|
Daily |
35.1% |
115.0% |
59.2% |
-99.2% |
|
Weekly |
-1.1% |
2.7% |
3.8% |
-48.8% |
|
Monthly |
-4.9% |
-24.6% |
-20.7% |
-9.8% |
|
Money |
||||
|
% off |
-3.6% |
-21.7% |
-18.7% |
-9.2% |
|
Discount |
-38.8% |
-59.2% |
-33.4% |
2.4% |
|
Free |
-10.3% |
-23.4% |
-14.7% |
-35.9% |
|
Half price |
9.7% |
-44.1% |
-49.1% |
51.2% |
|
Subscriptions |
||||
|
Last chance |
-16.5% |
-50.6% |
-40.8% |
24.1% |
|
Limited |
23.7% |
16.4% |
-5.9% |
-4.6% |
|
On sale now |
-2.8% |
0.9% |
3.8% |
-15.6% |
|
Subscription |
-5.3% |
-47.8% |
-44.8% |
68.1% |
|
Trial |
-45.6% |
-74.6% |
-53.3% |
-8.7% |
|
Miscellaneous |
||||
|
Deals |
7.3% |
-12.3% |
-18.3% |
53.6% |
|
|
-6.7% |
15.2% |
23.4% |
-58.9% |
|
iPad |
37.3% |
19.4% |
-13.1% |
16.9% |
|
|
12.2% |
18.1% |
5.3% |
-52.1% |
|
Source: Alestra, 2013 |
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TAKE-AWAY
The key to success is to "differentiate your offering in whatever way possible," concludes the report. Ineffective, confusing or ambiguous subject lines deliver "a poor user experience for their online journey."
About: To generate the statistics for this report, Adestra took a random sample of over 90,000 email campaigns, each with a list size of minimum 5000, for a total of over 2 billion emails. Adestra cautions that “lists may respond differently to the long-run averages” contained in the report, though the results should provide ideas on what should be tested.
Source: Alestra, 2013 Adestra Subject Line Analysis Report: Keywords for killer subject lines, accessed July 12, 2013.
