One column or two - Does multi-column displays effect readability?

The Software Usability Research Laboratory of Wichita State University have published a fascinating research paper entitled Is Multiple-Column Online Text Better? It Depends!, which looks at how multi column layout and text justification can effect readability and comprehension on the web.

In terms of reading speed they reported that;

• for one column of text, left justified is the fastest
• for two columns of text, fully justified is the fastest

Two columns of text, fully justified, was slightly faster overall then one column of text and both were significantly faster then 3 columns.

In terms of comprehension they reported that;

• they "found no significant main effects or interaction for either justification or number of columns for total comprehension"

but "In general, results from these analyses indicate that the fastest readers benefited most from the 2-column justified text, while the slowest readers performed best at the 1-column left justified format. In addition, satisfaction levels were found to be higher for the fast readers at the two-column full-justification condition than the other conditions."

Source: (UsabilityNews.com; Media: Usability News on Page Design for Screens)