Picking the Best Day To Send E-Mails

Should you e-mail your prospects on Monday or Friday, sometime in between or on the weekend?

Offering new insights into a question that has perplexed marketers since the beginning of the Internet, new data from eROI, an e-mail services firm, the "Q3 2005 Email Statistics" study found that the day of the week was not the only factor — beyond creative execution and offer — in determining e-mail marketing success.

"We decided to take a look at day of the week statistics by list size, and found that was beneficial in determining campaign value," said Jeff Mills, eROI e-mail analyst.

Key findings of the study show that overall read and click (or open and click-through) rates are the lowest during the middle of the week. The highest rates occur on Sunday and Friday. Generally speaking, as far as read and click statistics go, the middle of the week is the low point.

eROI went beyond the general data to look at the day-of-week statistics by list size. It studied mailings by "micro mailers," with lists under 5,000, "small mailers," with lists of 5,000 to 24,999, "midsize mailers," with lists of 25,000 to 99,999, and "large mailers," with lists over 100,000. And it found that size matters – a lot.

For large distribution lists, as has been traditionally surmised, Monday through Wednesday were found to be the best days to e-mail — posting a 32% increase in reads and just over twice as many clicks compared to the remaining days of the week.

eROI found that as list size increases, so do bounce rates, and read and click rates decline.

eROI analysts say these findings reaffirm their earlier research—namely, that sending volume is inversely related to how read and click rates. The bigger the list, the less efficient it will be. Of course, as with all rules, there is one exception: Saturday. eROI reports that lists over 200,000 tend to experience spikes in read rates on Saturdays, due probably to the fact that most of the larger lists are B2C and target consumers when they are likely to make shopping decisions (a good thing for B2C marketers to keep in mind).

One way large e-mail marketers might utilize the eROI findings is to break big lists down into smaller segments and treat different customers differently or, even better, utilize dynamic data to address them. Also, as the report recommends, "Consider removing individuals that are not reading your e-mails or separate them out into a different segment and mail to them less frequently and see how that affects the overall success rate of your campaigns."

How did other sized lists perform?

Micro mailers had read rates that averaged slightly over 35% and click rates between 5% and 9%. Those results are well above the broad average of 27% and 4.4%. The weekends were the best time for click-throughs, averaging 8% to 9% versus 5% to 6% for Tuesday through Thursday.

Small senders had average read rates and click rates of 27.8% and 4.7%, respectively. Friday was the best e-mail day, with a 31.2% read rate and a 5.3% click rate.

Mid-size senders registered wide swings in read and click behavior, with Monday and Friday being the most productive days (24.4/3.85 and 26.4/7.6, respectively).

Obviously, before marketers decide which day to e-mail, they need to ask themselves, "How big is my list?"

Article from www.eMarketer.com, 11 November 2005.