000			01672cam a2200229 4500
008			681114s1968 nyua b 001 0 eng
020			_a0471512400
040			_aDLC _cDLC
050	0	0	_aZ699 _b.L35
082	0	0	_a029 _bLAN
100	1		_aLancaster, F. Wilfrid
245	1	0	_aInformation retrieval systems : _bcharacteristics, testing, and evaluation /
260			_aNew York : _bJohn Wiley & Sons, _cc1968.
300			_axiv, 222 p. :ill,
504			_aIncludes bibliographical references and index
520			_a As Lancaster clearly recognizes, "The quality of the index language is probably the most important single factor governing the performance of a retrieval system." Cited data on the MEDLARS system show that all but 2 of the system failures stem directly or indirectly from the inability of users to ask successfully for what they want in these extremely restricted and cantankerous "index languages." As a result, the actual performance of current systems range from mediocre to atrocious. An outstanding feature of the text is a careful and comprehensive evaluation of one of the best of the systems, MEDLARS. Overall, about 58% of the pertinent items in MEDLARS files are retrieved on request. Only about 50% of the items that are retrieved turn out to be pertinent to the request. This is not very good performance particularly when it is remembered that an "information retrieval system does not inform the user on the subject of his inquiry. It merely informs him on the existence ... of documents
590			_arpm 27/07/2018
591			_aLoans
650		0	_aInformation storage and retrieval systems.
942			_2ddc _cBOOK
949			_a029 LAN
999			_c9421 _d9421