Leading email campaign provider Adestra (www.adestra.com) has released a report revealing which keywords in email subject lines cause higher open rates and which ones cause more unsubscribes than average.

It also reveals the best time and day to send emails–Tuesday at 4 p.m.

For law firms, based on results from the B2B campaigns Adestra studied, the words to use in subject lines for your newsletters and legal alerts are: bulletin, exclusive, latest, news, newsletter, research, and special.  All perform solidly above average.

The top subject line word to avoid caught us by surprise:  whitepaper.  It posted a 200 percent lower open rate than average.  Also avoid using the words alert, webinar, download, free and forecast.

Adestra’s report, a follow-up to its groundbreaking 2013 study of email subject lines looked at anonymized data from 3 billion emails from 125,000 email campaigns generating 400,000 opens and 55,000 clicks.

“If a key strategy for your business is to maintain long-lasting connections with prospects to ensure you are in the right place at the right time it is very important to avoid unsubscribes,” Adestra said, adding that “when unsubscribes happen in the B2B world it’s much more important, especially for high-value products with a convoluted sales process.”