I tend to write subject lines as statements. Research suggests I could be leaving readership on the table.

I have this habit with subject lines…

Even when they begin with words like How or Why, I tend to frame them as statements rather than questions.

Why Customers Choose the Familiar

instead of

Why Do Customers Choose the Familiar?

The first one has always seemed cleaner to me. More confident, I guess. Less clickbait-y.

A study I came across has me reconsidering that instinct.

Researchers at BI Norwegian Business School ran two field experiments comparing declarative headlines with question headlines in online communication.

In the first, they tested headlines on an X account used to share research news.

The results were pretty dramatic.

Question headlines without self-referencing language increased readership by an average of 150% compared with declarative versions.

When the questions included words such as you or your, the average increase was 175%.

The second experiment moved into a very different setting: classified ads for products including an iPhone, television, couch and washing machine.

Again, question headlines generally attracted more clicks.

And the biggest lift came from questions that pulled the reader personally into the headline.

For example:

“Is this your new iPhone 18?”

Across the four products, self-referencing question headlines increased readership by an average of 257% compared with declarative versions. 

There was (as always) an exception.

The washing-machine ads did worse with question headlines.

Which is useful, because this clearly isn’t a mechanical formula where adding a question mark magically doubles your response.

The topic and product still drive the outcome.

A statement gives you information.

And a question asks your brain to do something with it.

“Why Customers Abandon Their Shopping Carts” tells me what the article is about.

“Why Do Customers Abandon Their Shopping Carts?” creates a small unresolved task. It reaches me a bit differently.

And if I make it personal:

“Why Are YOUR Customers Abandoning Their Shopping Carts?”

now you may start mentally retrieving examples from your own business before you’ve even clicked.

The researchers point to exactly that kind of cognitive processing.

Questions can stimulate recall, curiosity and elaboration, while self-referencing language encourages us to connect the message to our own knowledge and experience.

I’ve probably resisted question headlines because bad ones are so… everywhere.

Are You Making These 7 Disastrous Marketing Mistakes???

Yarfff. No thanks.

But that doesn’t mean the punctuation is the problem.

One of the ideas I explore in I Need That is that tiny changes in how a product or message is framed can change the way folks process it.

Maybe the underlying content hasn’t changed, but the reader’s role has.

A statement lets me observe the idea.

But a good question makes me participate in it.

So I might experiment with a few more question marks in the Need Feed.

My data shows about a 2.5% lift in posts where the subject line is posed as a question across 750+ emails. Pretty minor.

But I will test this more, because I do wonder:

Have I been stubbornly writing the less clickable version all this time?

If you’d like help creating and marketing products people feel compelled to buy, the product marketing consultants at Graphos Product can help.