IRS13 Test Environment chapter E. M. Keen Harvard University Gerard Salton Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. 1-2 journal articles of a technical rather than popular nature, centering on high speed aerodynamics, and including a small number of documents on internal aerodynamics (flow in compressors, for example) and atmospheric re- entry. Most of the abstracts used are those that were written by the authors of the papers; a small number of documents which had no author abstract use a commercially published abstract. No documents in the col- lection were published later than 1962, and most papers fall between 1954 and 1963. The ADI collection comprises some of the "short papers' presented at the American Documentation Institute's Annual Meeting in 1963. Although most aspects of documentation are covered, the theme of the meeting was "Automation and Scientific Communication", and thus the collection emphasizes the research and mechanized rather than the operational and manual side of documentation. Fig. 1 gives counts of the average lengths of the documents, Cran-l being the longest, IRE-3 next, and ADI the shortest, except that in the case of ADI the full texts of the short papers are also available. The indexing that is available for the Cran-l collection is about half the length of the abstracts. Fig. 1 also gives similar dataf'[OCRerr]r[OCRerr]the search requests, showing that the IRE-3 requests are largest, followed by Cran-l and then ADI. The methods used for obtaining requests are briefly summarized in Fig. 1 The Cranfield requests were obtained from authors of research papers in aerodynamics and the requests cover the stated problems that the authors were investigating, which finally led to their research paper. Authors often supplied more than one request; 29 authors in all were /[OCRerr]ii[OCRerr][OCRerr]j. [OCRerr]