Make work visible. This end goal of requirements analysis can be elusive when work is not understood in the same way by all participants. Blomberg, Suchman, and Trigg (1996) discuss this in their exploration of image-processing services for a law firm. Their studies of the firm's attorneys produced a rich analysis of document processing needs for each legal proceeding, documents often numbering in the thousands are identified as "responsive" (relevant to the case) by junior attorneys, in order to be submitted for review by the opposing side. Every document page is given a unique number for retrieval purposes. An online retrieval index is created by litigation support workers; theindex encodes document attributes such as date, sender, recipient, and type.

The attorneys told the analysis team that it would be easier to make the relevance decisions if the documents could be processed automatically to encode their objective attributes (e.g., date and sender). However, studies of human document processing revealed activities that were not objective at all, but rather relied on the informed judgment of the support staff. Something as simple as a document date was often ambiguous, because the index might display the date it was written, signed, and/or delivered; the date encoded required understanding the document's content and role ina case. Even determining what constituted a document required judgment, as papers came with attachments and no indication of beginning or end. Taking the perspective of the support staff revealed knowledge-based activities that were invisible to the attorneys, but that had critical...