What else and where else: two worthwhile questions for an information interface

Abstract

We make a case for widespread support, in interfaces for retrieving and laying out information items, for two simple operations on the items being displayed. The operations are predicated on the fact that the calculations determining how items should be laid out, for example into a ranking, are often highly sensitive to criteria that, for a given application, are somewhat arbitrary. Subtly different criteria can lead to dramatically different results. Our suggestion is to support users in understanding such differences among multiple result displays, with a 'What else?' operation that shows which items appear in a given location in any of those displays, and conversely a 'Where else?' that shows other locations where a given item can appear.