Publication: The Usability of Stacked-Block Overviews for Retrieval

Stacked-block overviews represent a large data set in a compact space by placing items in a closely-packed grid. As awareness displays, they provide a bird's-eye view of state, activity, and change in a data set. However, stacked-block overviews have a distinct disadvantage when it comes to retrieval, because they provide few clues to the identity of objects other than spatial position. To investigate the usability of stacked-block overviews, we carried out two studies in which participants retrieved items from either an overview or a standard scrolling list. Retrieval performance with the stacked-block overview was much better than we initially expected (and at its best was significantly better than the scrolling list), and several people strongly preferred the overview. However, the stacked-block representation was unusable for nearly a quarter of the participants, and even those who succeeded with it required extensive training to reach a high level of performance. Despite these problems, our results show that stacked-block overviews can in many cases be used as more than just awareness displays.




Carl Gutwin
University of Saskatchewan


Gutwin, C. 2005. The Usability of Stacked-Block Overviews for Retrieval., Technical Report HCI-TR-05-02, Computer Science Department, University of Saskatchewan.


@techreport {blocks-TR,
author= {Carl Gutwin},
title= {The Usability of Stacked-Block Overviews for Retrieval},
year= {2005},
number= {HCI-TR-05-02},
school= {Computer Science Department, University of Saskatchewan}