P. G. Wojahn, C. M. Neuwirth, and B. Bullock. Effects of interfaces for annotation on communication in a collaborative task. In CHI98: Human Factors in Computing Systems, Conference Proceedings, pages 456–463, Los Angeles, CA, USA, April 18-23 1998. Association for Computing Machinery. [url]
This paper present a solid study on the effect of annotation interface on collaborative writing. The authors compared three types of interfaces: a split screen interface, where the annotations are presented in a separated footnote-style panel; a interlinear interface, where comments are differenciated from the text through formatting features; and finally aligned interface where the annotations are visible “at-a-glance” horizontally aligned to the primary text with which they are associated, but in a distinct space in the margin.
The authors found that time on task did not vary significantly across conditions and did not interact with dependent measures. Additionally an LSD ANOVA indicated that those in the interlinear and aligned conditions communicated about significantly more problems than those in the split-scree condition. Also, subjects in these two conditions communicated about more equivocal problems than subjects in the split-scren condition.
They results were contrary to their hypothesis that interface effects would be greatest when problems are most difficult. The author pointed to a possible explaination for these results from the computer-mediated communication literature: humans compensate for greater communication difficulties not sacrificing the production of important ideas but communicating those ideas more tersely.