ISR11 A Modified Two-Level Search Algorithm Using Request Clustering chapter V. R. Lesser Harvard University Gerard Salton Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. vII-28 effectivencss. It is felt that this new criterion based completely on the position of relevant doc[OCRerr][OCRerr]ents is an adequate indicator of relevant search effectiveness of the modified and normal two-level search schemes. 7. Conclusions The limited test data available, an& the restrictions placed on the e[OCRerr]eriment have not all[OCRerr]Ted a definitive evaluation of the modified and normal two-level search schemes. It ha3 however been sh[OCRerr][OCRerr]n that the modified two-level search has potential merit and should be investigated more thorou&hly. Hopefully, this report provides an outline for future research into the development of this new search technique.