As I'm sure you know, various other marketers teach that one should write headlines no longer than 17 words. Whereas others teach that headlines should be real short as their testing has shown those headlines to pull better than long ones.
Here's my answer.
Either one is fine. I usually like to test both.
Granted, I'm a follower of Dan Kennedy, who's a big believer in long headlines. And I've tested short headlines, too, and they do pull better in terms of response, clickthroughs and readership.
But not necessarily sales.
My theory? Perhaps smaller headlines (and I do mean good ones) don't offer enough information, so they pull people in. Which is a good thing…
… *IF* they are qualified.
Long headlines tend to prequalify readers. If they hit your website or salesletter and fail to read further because a long headline offers too much information, that's good in my opinion. They weren't qualified to read a long copy salesletter either — much less the offer. Tire kickers.
Again, I'm speaking strictly for long direct response copy. Short copy may be totally different. And I do use short headlines if it tells the story I want it to tell. Sure, it's best to pithisize as much as possible (as copywriter John Carleton calls it)… But not at the expense of telling the story that's needed to qualify readers AND pull them into the copy.
From my experience, I've tested both — sales conversion on copy with short headlines underperformed the longer ones almost every time.
(Now, a caveat — doesn't mean to use one big sentence and doesn't mean using a long headlines that doesn't give you a chance to come up for air while reading it. A long headline can have 2, 3 or more sentences. I also used split-headlines — 2-3 headlines. And they worked extremely well.)