Based on our prior experience with WISRs '91, '92, and '93, the position paper should be no longer than 3-5 pages, about 2000 words. It should be written specifically as a position paper, rather than as a regular research paper.
The goal is to highlight succinctly your involvement, interest, and experience with reuse, and to state a position, hypothesis, opinion, theory, research or practical result that will enable the selection committee to quickly determine what area your work addresses, and your contribution/involvement with the workshop.