This latest study from Adestra follows from its July 2012 report, which was not limited to the B2B sector.
What Works, And What Doesn’t
Adestra’s subject line study takes a look at subject line keyword metrics across a variety of themes, scoring them by relative open, click, and click-to-open rate. Below, a summary of the results by theme.
- Currency symbols: Subject lines containing the £ symbol had a far better-than-average (57.8%) click-to-open rate. Those with $ signs scored above-average in opens (15.7%) and clicks (14.7%), but slightly below-average in click-to-opens (-0.8%). Subject lines containing the € symbol were above-average in opens (2.9%) but below-average in clicks (-8.2%) and click-to-opens (-10.8%). Of course, targeting has a big effect on this – as some symbols may be irrelevant to the recipient.
- Discount terms: These generally performed below-average. “Sale” was the outlier, above-average in opens (14.4%), clicks (76.5%), and click-to-opens (54.3%). Others such as “% off,” “discount,” “free,” “half price,” “save,” “voucher,” “early bird,” and “2 for 1″ all came in below-average in all 3 metrics, save for “voucher,” which had above-average opens (6.5%). “Early bird” was the worst performer in terms of clicks (-71.6%) and click-to-opens (-67.6%).
- News terms: These had better success than discount terms. “News” (16.2%), “update” (4.9%), “breaking” (33.5%), “alert” (25.9%), and “bulletin” (12.5%) all saw better-than-average click-to-open rates (as well as clicks and opens), with “newsletter” being the only term to perform below-average in each metric. “Alert” saw the best differential for clicks (78.3%), while “news” did best for opens (30.9%).
- Content terms: There were more discrepancies in this theme. “Issue” (8.5%) and “top stories” (5.9%) were the only to perform above-average in click-to-opens, although the latter saw slightly below-average open and click rates. “Forecast,” “report,” “whitepaper,” and “download” all saw below-average performance in each of the 3 metrics. “Research,” “interview,” and “video” scored above-average for opens, but below-average for clicks and click-to-opens.
- Benefit terms: “Latest” was the only to see above-average clicks (8.8%) and click-to-opens (9%), while “special,” “exclusive,” and “innovate,” while performing about average in opens, fared far more poorly in clicks and click-to-opens.
- Event terms: Each of these terms performed below-average in opens, clicks, and click-to-opens. The terms examined were: “exhibition,” “conference,” “webinar,” “seminar,” “training,” “expo,” “event,” “register,” and “registration.” The worst offender for click-to-opens was “webinar” (-63.5%).
- Multichannel terms: Facebook (21.6%) and Pinterest (16.4%) were the only terms to score above-average in clicks and click-to-opens, though both showed below-average performance in opens. On the flip side, “app” and “iPad” were above-average in opens, and below-average in clicks and click-to-opens. Both “Twitter” and “LinkedIn” were below-average in all 3 metrics.
Personalization Helps Opens, Fails on Clicks
Further details from the report reveal that personalized subject lines generate significant engagement from recipients in the sense that they are 22.2% more likely to be opened. However, beyond opens, the results are decidedly worse. Personalized emails had a click rate 16.5% lower than the average, and a click-to-open rate 31.7% below the average. The researchers suggest that engagement worsens after the email open because personalization starts and ends in the subject line, and the content itself lacks personalization.
A Word About Subject Line Length
The study also examined subject line length, finding that those with 30 or less characters performed above-average in opens, clicks, and click-to-opens, while those with more than 90 characters did even better. In between, the results were closer to the average, with the 60-90 character length group faring worst.
The word count analysis follows a similar pattern. “Snappy” subject lines of 1-2 words easily performed best in each of the metrics, while those with more than 14 words also performed above-average. All other word count groups skewed closely to the average.
Of course, as the report illustrates, the words chosen for those subject lines have much to do with the success of the email.
About the Data: The Adestra report contains the following notes:
“The following research was taken from a sample of delivered email campaigns for the B2B sector resulting in an average correlation of statistics. Email marketers are advised to test their email campaigns in order to determine the optimum subject line combinations. Although subject line best practice has been advised throughout the document, we strongly advise email marketers to use relevant content and clean data in conjunction with optimised subject lines in order to realise maximum result improvements.”