Monday, October 26, 2009

100 Things You Should Know about People: #2 -- Line Length

Have you ever had to decide how wide a column of text you should use on a screen? Should you use a wide column with 100 characters per line? or a short column with 50 characters per line?

It turns out that the answer depends on whether you want people to read faster or whether you want them to like the page!

Research (see reference below) demonstrates that 100 characters per line is the optimal length for on-screen reading speed; but it's not what people prefer. People read faster with longer line lengths (100 characters per line), but they prefer a short or medium line length (45 to 72 characters per line). In the example above from the New York Times Reader, the line length averages 39 characters per line.

The research also shows that people can read one single wide column faster than multiple columns, but they prefer multiple columns (like the New York Times Reader above).

So if you ask people which they prefer they will say multiple columns with short line lengths. Interestingly, if you ask them which they read faster, they will insist it is also the multiple columns with short line lengths, even though the data shows otherwise.

It's a quandary: Do you give people what they prefer or go against their own preference and intuition, knowing that they will read faster if you use a longer line length and one column?

What would you do?

Dyson, M.C. (2004). "How Physical Text Layout Affects Reading from Screen." Behavior & Information Technology, 23(6), pp. 377-393.


El Gitano said...

Hello, Susan! First of all let me say that I'm an assiduous portuguese reader of your blog and that I translate, adapt and comment some of your posts to portuguese in my Blog!

My answer to this question reminds me the teachings of another guru of accessibility/usability (Jakob Nielsen) that tells us that we should give more importance to what user says rather than what the users do.

However, the answer is not so simple. According to my superficial reading of the paper, the study does not quantify the gains in speed against the number of characters per line and the understanding of the text. I mean that the gains may not justify the final appearance of the page (less appealing to users). More important than the number of characters per line is the text being adapted for the Web. Nobody likes to read large portions of text on the screen. If your goal is to get users to read a novel or other large literature on screen, then you should use the proven techniques that make easier the reading.

Susan Weinschenk said...

Yes, thanks for your comments. I agree that people don't like to read on a screen and there are things you need to do to make text more readable (another one of the 100 things that I'll get to in one of these blogs). We do, however, have to deal with this issue of preference vs. performance in many areas, line length being one of them. It's a philosophical decision we have to continualy make I believe.

El Gitano said...

Just to say that my previous message had an error! When I say "we should give more importance to what user says rather than what the users do" I meant "we should give more importance to what users DO rather than what the users SAY".