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Bernard, M., Fernandez, M. and Hull, S., (2002), The effects of line
length on children and adults' online reading performance, Usability
News, 4.2.
Baker, J.R., (2003), The Impact of paging vs. scrolling on reading online
text passages, Usability
News, 5.1.
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In the November 2002 issue of the HFI newsletter, Bob Bailey discussed
the research on optimal line length when reading text on a monitor. He
concluded that users read faster if the line lengths are longer (up to
10 inches), but users tend to prefer lines that are moderately long (4
to 5 inches). Some of the research he cites is recent, but some predates
computers. I suggest that the research results are not so clear cut.
This issue of the newsletter takes a close look at two recent research
studies. Dr. Bailey referenced one study by Bernard, Fernandez, and Hull.
I'd like to take a closer look at that study here, and review even more
recent results that just came out in 2003.
In the Bernard, Fernandez, and Hull study from 2002, the researchers
used both adults (ages 18 to 61, median of 29) and children (ages 9 to
12). They used 3 different line lengths:
- full distance (132 characters per line, or CPL),
- medium (76 CPL), and
- short (45 CPL).
They found no significant differences on reading time for either children
or adults when comparing the different lengths.
But when they asked a series of preference questions they got some interesting
and statistically significant results. The adults said it was easier to
concentrate on the narrow length than both the medium and full length
(statistically significant at p<.01). The children did not have any
significant difference on perceived concentration.
Both children and adults had definite preferences. No adults chose the
full length as their favorite. Most chose medium length, and narrow length
was not far behind. For the children the full length was also the least
preferred, with a strong preference for the narrow length.
The researchers were also interested in the relationship between scrolling
and line length. They asked the adults which condition had the optimal
amount of scrolling, and there was a significant difference there –
the full length condition was perceived as more optimal for scrolling
than the medium or short line lengths.
So adults prefer a medium line length, children a narrow length, even
though this preference doesn't translate into faster reading. But what
about the scrolling? Is vertical scrolling for reading really bad? Should
we use longer line lengths because it has less scrolling? Is people's
preference for less scrolling more important than their preference for
medium or narrow line lengths?
Another study by Ryan Baker adds more interesting results to ponder.
Baker set up three online reading conditions:
- paging where there was no scrolling required and the users read a
page of text with a medium line length and then used a page forward
button to go to the next page and the next,
- a "full" condition where there was some scrolling as well
as a page forward key, and
- a scrolling condition which had no paging, but required a lot of scrolling.
Results of the study showed that users took significantly longer to read
a passage in the paging condition than in the other conditions. The areas
that showed no significant differences are telling as well. There were
no significant differences in any of the following: perception that a
particular condition was more well-suited for reading, that one condition
made information easier to find, or that a particular layout was better
for comprehension.
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