Subject lines can increase email open rates and may also have a significant impact on final conversion rates.

Subject lines often don't get the attention they deserve from writers. But these short lines have a significant effect on open rates, clickthrough rates and final conversions to sales.

One of several factors that can make a difference is specificity.

Recently we conducted a test of two subject lines with one of our research partners.

Both subject lines included an element of urgency. But the second version was much more specific with its message. In other words, it didn't just mention an offer deadline, but also included the name of the specific group of products on offer.

While we are not entirely satisfied with the level of validity of the results so far, and the test is still ongoing, we do have a sufficient level of confidence to conclude that a more specific offer in an email subject line will increase final conversion to sales.

Here are the results from that test:

By adding the names of the courses on offer, we increased conversion by 89.57 percent.

Email and newsletter subject lines need to address a number of important issues. Those few words need to help a reader recognize your company and remember the value of what you have emailed before... they need to express urgency... and they need to be specific in their promise.

It is not easy to achieve all these things in the few words available in a subject line. But when you work hard at it, the impact on open rates, clickthroughs and conversion to sales can be significant.

You'll find a full archive of our test results, and analysis within the MarketingExperiments.com Research Archives. The Marketing Experiments Journal publishes primary test results from work with our research partners once every two weeks. Subscription to the Journal is free and gives you full access to both our archives and teleconference calls. Subscribe here.