Study: Email marketers should play percentages

Retailers sending email promotions may want to hold off on announcing deals that offer a specific number of dollars off the listed price.



According to a new study of more than one billion marketing emails by retention marketing firm Retention Science, customers are more receptive to percent-off deals than dollar-off deals. Percent-off deals result in customers 38% more likely to click, and 47% more likely to convert when they were presented with a dollar-off offer.



Punctuation also impacts email open rates. The presence of any type of punctuation mark increased open rates by 9%. Question marks are particularly effective at engaging recipients. In fact, the study found subject lines with question marks have open rates 44% greater than those with exclamation points.



Six to 10 words is still the optimal length for email subject lines, ranking highest for open rates (21%) for the second year in a row. Second highest is zero to five words, with a 16% open rate. The rates start to fall significantly in the 11- to 15-word range, with emails only opened 14% of the time, and results only decrease from that point.



While open rates are consistent throughout the year, click rates are highest at the beginning of the holiday season, reaching 30% in October and 27% in November. Likely due to Fourth of July holiday sales, July has the best conversion rate of any month, with rates 21% higher than average. December ranks second, with rates 10% above the norm.



Retention Science found unsubscribe rates are highest during the month of August, with 28% of respondents unsubscribing. Unsubscribe rates tend to be lower in the holiday-season, such as November (4%) and December (5%), likely because consumers are on the lookout for deals and gift suggestions. Marketers may also want to amp up their efforts in April and October, which also see above-average unsubscribe rates (8% and 9%, respectively).



Subject lines that mention novelty items generate more interest, showing a 6% lift in open rates. Common goods such as groceries and personal basics have a 10% higher click-through rate than novelty or specialty items, even when the novelty item was featured in the subject line. This may be because novelty items tend to be higher priced, and people need to replenish basics more often.